Ronnie invested $1500 in an account that earns 3.5% interest, compounded annually. The formula for compound interest is A(t) = P{(1 + i)^t}A(t)=P(1+i) t . How much did Ronnie have in the account after 4 years?

Answer:

B. 8

Step-by-step explanation:

The question lacks the required diagram. Find the diagram in the attachment.

Before we can find d21, d22 and d23, we need to get the matrix D first as shown in the attached solution.

On comparison as shown in the attachment, d21 = 11, d22 = -10 and d23 = 7

Note that d21 refers to element in the second row and first column of the matrix

d22 is the element in the second row and second column of the matrix

d23 is the element in the second row and third column of the matrix

d21+d22+d23 = 11-10+7

d21+d22+d23 = 8

The second option is correct.

Answer:

D

Step-by-step explanation:

It would be a cone with a radius of 4 units rotating around y-axis.

[tex]1. \: (x - y) {2} \\ = {x}^{2} - 2xy + {y}^{2} \\ 2. \: (a + b) ^{2} \\ = {a}^{2} + 2ab + {b}^{2} \\ 3. \: (2x + 3y) ^{2} \\ = {(2x)}^{2} + 2.2x.3y + (3y) ^{2} \\ = {4x}^{2} + 12xy + {9y}^{2} \\ 4.(3x - 2y) ^{2} \\ = (3x) ^{2} - 2.3x.2y + (2y) ^{2} \\ = {9x}^{2} - 12xy + {4y}^{2} \\ hope \: it \: helps \\ good \: luck \: on \: your \: assignment[/tex]

Answer:

a) x^2−2xy+y^2

b) a^2 -ab+b^2

c)4x^2+12xy+9y^2

d)9x^2 -12xy+4y^2

Step-by-step explanation:

a) x^2−2xy+y^2

b) a^2 -ab+b^2

c)4x^2+12xy+9y^2

d)9x^2 -12xy+4y^2

We rewrite (x-y)^2 as (x-y) (x-y) to show and always see + sign at start for question a ) and question b)

a) x*x+x(−y)−yx−y(−y) = x^2−2xy+y^2

b) a^2 becomes a^2 -ab as a^2 -ab+b^2

c) As shown in notes attached and this will help you most.

d) the reasons we keep +4y is because -2y becomes -2y-2y and creates a plus.

Answer:

11

Step-by-step explanation:

h(t) =|t +2| + 3

Let t=6

h(6) =|6 +2| + 3

       = |8| +3

        =8+3

         = 11

Answer:

0.3537 feet per minute.

Step-by-step explanation:

Gravel is being dumped from a conveyor belt at a rate of 10 ft3/min. Since we are told that the shape formed is a cone, the rate of change of the volume of the cone.

[tex]\dfrac{dV}{dt}=10$ ft^3/min[/tex]

[tex]\text{Volume of a cone}=\dfrac{1}{3}\pi r^2 h[/tex]

If the Base Diameter = Height of the Cone

The radius of the Cone = h/2

Therefore,

[tex]\text{Volume of the cone}=\dfrac{\pi h}{3} (\dfrac{h}{2}) ^2 \\V=\dfrac{\pi h^3}{12}[/tex]

[tex]\text{Rate of Change of the Volume}, \dfrac{dV}{dt}=\dfrac{3\pi h^2}{12}\dfrac{dh}{dt}[/tex]

Therefore: [tex]\dfrac{3\pi h^2}{12}\dfrac{dh}{dt}=10[/tex]

We want to determine how fast is the height of the pile is increasing when the pile is 6 feet high.

[tex]When h=6$ feet$\\\dfrac{3\pi *6^2}{12}\dfrac{dh}{dt}=10\\9\pi \dfrac{dh}{dt}=10\\ \dfrac{dh}{dt}= \dfrac{10}{9\pi}\\ \dfrac{dh}{dt}=0.3537$ feet per minute[/tex]

When the pile is 6 feet high, the height of the pile is increasing at a rate of 0.3537 feet per minute.

Simplifying

23 + 11a + -2c = 12 + -2c

Add '2c' to each side of the equation.

23 + 11a + -2c + 2c = 12 + -2c + 2c

Combine like terms: -2c + 2c = 0

23 + 11a + 0 = 12 + -2c + 2c

23 + 11a = 12 + -2c + 2c

Combine like terms: -2c + 2c = 0

23 + 11a = 12 + 0

23 + 11a = 12

Solving

23 + 11a = 12

Solving for variable 'a'.

Move all terms containing a to the left, all other terms to the right.

Add '-23' to each side of the equation.

23 + -23 + 11a = 12 + -23

Combine like terms: 23 + -23 = 0

0 + 11a = 12 + -23

11a = 12 + -23

Combine like terms: 12 + -23 = -11

11a = -11

Divide each side by '11'.

a = -1

Simplifying

a = -1

Answer:

Step-by-step explanation:

Hello!

The objective is to test if the proportion of "X: gloves fitness, categorized: Fit poorly and Fit well" is the same for two populations of interest, "male firefighters" and "female firefighters"

To do this you have to conduct a Chi-Square test of Homogeneity.

In the null hypothesis you have to state that the proportion of the  categories of the variable are the same for all the populations of interest.

Be

M: the firefighter is male

F: the firefighter is female

Y: represents the category that the gloves "fit poorly"

W: represents the category that the gloves "fit well"

The null hypothesis will be:

H₀: P(Y|M)=P(Y|F)=P(Y)

P(W|M)=P(W|F)=P(W)

H₁: At least one of the statements in the null hypothesis is false.

α: 0.01

To calculate the statistic under the null hypothesis you have to calculate the expected frequencies first:

[tex]E_{ij}= O_{.j}*\frac{O_{i.}}{n}[/tex]

O.j= total of the j-column

Oi.= total of the i-row

n= total of observations

[tex]E_{11}= 547*\frac{152}{586} = 141.88[/tex]

[tex]E_{12}=39*\frac{152}{586}= 10.12[/tex]

[tex]E_{21}= 547*\frac{434}{586} = 405.12[/tex]

[tex]E_{22}= 39*\frac{434}{586} = 28.88[/tex]

[tex]X^2= sum \frac{(O_{ij}-E_{ij})^2}{E_{ij}} ~~~X^2_{(r-1)(c-1)}[/tex]

r= number of rows (in this case 2)

c=number of columns (in this case 2)

[tex]X^2_{H_0}= \frac{(132-141.88)^2}{141.88} +\frac{(20-10.12)^2}{10.12} +\frac{(415-405.12)^2}{405.12} +\frac{(19-28.88)^2}{28.88} = 13.95[/tex]

Using the critical value approach, you have to remember that this test is always one-tailed to the right, meaning that you'll have only one critical value from which the rejection region is defined:

[tex]X^2_{(r-1)(c-1);1-\alpha }= X^2_{1;0.99}= 6.635[/tex]

The decision rule is then:

If [tex]X^2_{H_0}[/tex] ≥ 6.635, reject the null hypothesis.

If [tex]X^2_{H_0}[/tex] < 6.635, do not reject the null hypothesis.

The calculated value is greater than the critical value, the decision is to reject the null hypothesis.

So at a 1% level you can conclude that this test is significant. This means that the proportions of gloves fitness, categorized in "Fit poorly" and "Fit well" are different for the male and female firefighters populations.

I hope this helps!

Answer:

The Chi - Square Test Statistics is  13.98

p-value = 0.0002

CONCLUSION: Since the p-value is less than the level of significance ; (i.e p-value < ∝) we reject the null hypothesis and accept the alternative hypothesis.

Thus; there is a difference in the population proportion of glove fitness for the two genders.

Step-by-step explanation:

From the information given ; the structure of the table can be well represented as follows;

Observed data                  Males                    Females             Total

Gloves fit poorly                132                         20                       152

Gloves fit well                    415                         19                        434

Total                                   547                        39                       586

Expected data                  Males                   Females              Total

Gloves fit poorly

Gloves fit well

Total

The objective of this question is to  use the chi-square test to determine if there is a difference in the population proportion of glove fitness for the two genders.

We call represent the hypothesis as follows:

The null hypothesis: [tex]H_o:[/tex] states that there is no difference  in the population proportion of glove fitness for the two genders.

The alternative hypothesis: [tex]H_a[/tex] states that there is difference  in the population proportion of glove fitness for the two genders.

The expected frequency of a particular cell can be calculated by multiplying the sum of the rows and columns together, then dividing it by the Total sum

For row 1 column 1 (gloves fit poorly (male) ; we have:

[tex]= \dfrac{547*152}{586} =141.884\\[/tex]

For row 2 column 1 (gloves fit well(male) ; we have:

[tex]= \dfrac{547*434}{586} =405.116[/tex]

For row 1 column 2 (gloves fit poorly (female)) ; we have:

[tex]= \dfrac{39*152}{586} =10.116[/tex]

For row 2 column 2 ( gloves fit well ( female ) ; we have:

[tex]= \dfrac{39*434}{586} =28.884[/tex]

Thus; we can have the complete table to now be:

Observed data                  Males                    Females             Total

Gloves fit poorly                132                         20                       152

Gloves fit well                    415                         19                        434

Total                                   547                        39                       586

Expected data                  Males                   Females              Total

Gloves fit poorly                141.884                 10.116                  152

Gloves fit well                    405.116                28.884                 434

Total                                    547                        39                     586

The Chi - Square Test Statistics can be calculated via the formula:

[tex]X^2 = \dfrac{\sum (f_o-f_e)^2}{f_e}[/tex]

where;

[tex]f_o[/tex] = observed data frequency

[tex]f_e[/tex] = expected data frequency

∴

The Chi - Square Test Statistics is as follows:

[tex]=\dfrac{(131-141.884)^2}{141.884} + \dfrac{(20-10.116)^2}{10.116}+ \dfrac{(415-405.116)^2}{405.116}+ \dfrac{(39-28.884)^2}{28.884}[/tex]

= 0.68+9.6+0.2+3.5

= 13.98

We are given the level of significance ∝  to be = 0.01

numbers of rows = 2; number of column = 2

Thus; the degree of freedom = (2-1)(2-1) = 1×1 = 1

Using the Excel Function : [ = CHISQ.DIST.RT²(X²,df)]

p-value = 0.0002

CONCLUSION: Since the p-value is less than the level of significance ; (i.e p-value < ∝) we reject the null hypothesis and accept the alternative hypothesis.

Thus; there is a difference in the population proportion of glove fitness for the two genders.

Answer:

21 and 10.5 respectively

Step-by-step explanation:

Remember circumference of a circle is given as;

C= 2×π×r; r is raduis

r = C / 2×π

=65.98/(2×3.142)= 10.50

D= 2× r = 2× 10.50= 21.0( D represent diameter)

Note π = 3.142 a known constant

Answer:

14 units

Step-by-step explanation:

The perimeter of a figure is the sum of the lengths of all the sides.

Here, we know that ABCD is a rectangle, so by definition, AB = CD and AD = BC. We also are given that AB = 3y + 3 and BC = 2y, which means that:

AB = CD = 3y + 3

AD = BC = 2y

Adding up all the side lengths and setting that equal to the perimeter, which is 76 units, we get the expression:

AB + CD + AD + BC = 76

(3y + 3) + (3y + 3) + 2y + 2y = 76

10y + 6 = 76

10y = 70

y = 7

We want to know the length of AD, which is written as 2y. Substitute 7 in for y:

AD = 2y = 2 * 7 = 14

The answer is thus 14 units.

~ an aesthetics lover

Answer:

14

Step-by-step explanation:

The perimeter of a rectangle is found by

P = 2 (l+w)

P = 2( 3y+3+2y)

Combine like terms

P = 2(5y+3)

We know the perimeter is 76

76 = 2(5y+3)

Divide each side by 2

76/2 = 2/2(5y+3)

38 = 5y+3

Subtract 3 from each side

38-3 = 5y+3-3

35 = 5y

Divide each side by 5

35/5 = 5y/5

7 =y

We want the length of AD = BC = 2y

AD = 2y=2*y = 14

Answer:

3 sqrt(5) =c

Step-by-step explanation:

We can use the pythagorean theorem

a^2 + b^2 = c^2

3^2 + 6^2 = c^2

9+36 = c^2

45 = c^2

Take the square root of each side

sqrt(45) = sqrt(c^2)

sqrt(9)sqrt(5) = c

3 sqrt(5) =c

Step-by-step explanation:

20fruits=100%

5fruits=?

5x100/20 5fruitsx5%

=24%

Answer:

A:

Step-by-step explanation:

Using tangent-secant theorem

AE²=(EC)(ED)

12²=(8)(8+x+10)

144=8(x+18)

144=8x+144

8x = 144-144

8x = 0

So

x = 0

Now

ED = 8+x+10

ED = 8+0+10

ED = 18

Answer:

[tex]51[/tex]

Step-by-step explanation:

[tex]\frac{25.5}{0.5}[/tex]

[tex]\frac{255}{5}[/tex]

[tex]=51[/tex]

Answer:

see below

Step-by-step explanation:

i is the imaginary number and it represents the square root of -1

Answer:

[tex] \bar x = 40, s =10[/tex]

And from these values we can estimate the sample variance like this:

[tex] s^2 = 10^2 =100[/tex]

And we can also estimate the coeffcient of variation given by:

[tex] \hat{CV} =\frac{s}{\bar x}[/tex]

And replacing we got:

[tex] \hat{CV} = \frac{10}{40}= 0.25[/tex]

And this coefficient is useful in order to see the variability in terms of the mean for this case since is lower than 1 we can conclude that this variation around the mean is low.

Step-by-step explanation:

For this case we have the following info given:

[tex] \bar x = 40, s =10[/tex]

And from these values we can estimate the sample variance like this:

[tex] s^2 = 10^2 =100[/tex]

And we can also estimate the coeffcient of variation given by:

[tex] \hat{CV} =\frac{s}{\bar x}[/tex]

And replacing we got:

[tex] \hat{CV} = \frac{10}{40}= 0.25[/tex]

And this coefficient is useful in order to see the variability in terms of the mean for this case since is lower than 1 we can conclude that this variation around the mean is low.

Answer: At the end, you have $750 remaining in the bank.

Step-by-step explanation:

I guess you want to know how much is left in the bank.

initially

Hand : $1000

Bank: $1000

you withdraw $250 from the bank:

Hand: $1000 + $250 = $1250

Bank: $1000 - $250 = $750

Answer:

3:12

Step-by-step explanation:

Answer:

1:3

Step-by-step explanation:

Think 4:12 as a fraction for a moment, it would be 4/12. Now completely simplify 4/12, you get 1/3. Now put 1/3 as a ratio, it would be 1:3.

Please mark BRAINLIEST, thanks!

Answer:

40%

Step-by-step explanation:

To find the answer to this, you first can find out what percentage of students did wear spirit shirts. To do this you can divide 135 by 225 to give you 0.6. To convert the decimal into a percentage you can simply multiply by 100, giving you 60%. Then to find the percentage of students that did not wear spirit shirts, you can subtract 60 from 100, giving you 40%.

Here is the full question.

The average finishing time among all high school boys in a particular track event in a certain state is 5 minutes 17 seconds. Times are normally distributed with standard deviation 12 seconds.

A.  The qualifying time in this event for participation in the state meet is to be set so that only the fastest 5% of all runners qualify. Find the qualifying time in seconds (round it to the closest second). (Hint: Convert minutes to seconds.)  

B. In the western region of the state the times of all boys running in this event are normally distributed with standard deviation 12 seconds, but with mean 5 minutes 22 seconds. Find the proportion of boys from this region who qualify to run in this event in the state meet. (Hint: normalcdf)

Answer:

a. x ≅ 337 seconds.

b. P(x > 337 )  = 0.1056

Step-by-step explanation:

A.

Given that ;

Mean [tex]\mu =[/tex] 5 minutes 17 seconds =( (60× 5)+17  ) seconds  = 317 seconds   ( since 60 seconds make 1 minute.

Standard deviation: [tex]\sigma[/tex] = 12 seconds.

Only the fastest 5% of all runners qualify

The objective is to determine the qualifying time in seconds

Let's look for the Z-score of 0.95;

The Z-score is 1.645 from the tables

[tex]x= ( \sigma * z ) + \mu[/tex]

[tex]x = ( 12 * 1.645 ) + 317 \\ \\x = 336.74[/tex]

x ≅ 337 seconds.

B. Given that the standard deviation = 12 seconds

Mean = 5 minutes 22 seconds = (5 × 60 + 22 )seconds = 322 seconds

he objective is  to find P(x > 337 )   i.e the proportion of boys from this region who qualify to run in this event in the state meet.

we are using command normalcdf   (SEE THE ATTACHED FILE BELOW FOR THE COMPUTATION)

we have  P(x > 337 )  = 0.1056

Answer:

When x is 2, y is 16

Step-by-step explanation:

If y is 48 and x is 6, then y is 8 when x is 1.

Because of this, when x is 2, y will be 16.

Please mark Brainliest

Answer:

The probability is 0.31

Step-by-step explanation:

To find the probability, we will consider the following approach. Given a particular outcome, and considering that each outcome is equally likely, we can calculate the probability by simply counting the number of ways we get the desired outcome and divide it by the total number of outcomes.

In this case, the event of interest is  choosing 3 laser printers and 3 inkjets. At first, we have a total of 25 printers and we will be choosing 6 printers at random. The total number of ways in which we can choose 6 elements out of 25 is [tex]\binom{25}{6}[/tex], where [tex]\binom{n}{k} = \frac{n!}{(n-k)!k!}[/tex]. We have that [tex]\binom{25}{6} = 177100[/tex]

Now, we will calculate the number of ways to which we obtain the desired event. We will be choosing 3 laser printers and 3 inkjets. So the total number of ways this can happen is the multiplication of the number of ways we can choose 3 printers out of 10 (for the laser printers) times the number of ways of choosing 3 printers out of 15 (for the inkjets). So, in this case, the event can be obtained in [tex]\binom{10}{3}\cdot \binom{15}{3} = 54600[/tex]

So the probability of having 3 laser printers and 3 inkjets is given by

[tex] \frac{54600}{177100} = \frac{78}{253} = 0.31[/tex]

Answer:

x<_ 21

Step-by-step explanation:

5(x+27)>_ =6(x+26)

5x +135 >_ 6x +156

5x >_6x +21

-x>_21

x<_21

Answer:

[tex]13t^2[/tex] feet higher the stone will travel on the other plant than on Earth.

Step-by-step explanation:

Initial velocity of the stone thrown vertically = 79 ft/s

It is given that:

Height attained on a different planet with time [tex]t[/tex]:

[tex]s_p = 79t -3t^2[/tex]

Height attained on Earth with time [tex]t[/tex]:

[tex]s_e = 79t -16t^2[/tex]

If we have a look at the values of [tex]s_p\text{ and }s_e[/tex], it can be clearly seen that the part [tex]79t[/tex] is common in both of them and some values are subtracted from it.

The values subtracted are [tex]3t^2\text{ and } 16t^2[/tex] respectively.

[tex]t^2[/tex] can never be negative because it is time value.

So, coefficient of [tex]t^2[/tex] will decide which is larger value that is subtracted from the common part i.e. [tex]79t[/tex].

Clearly, [tex]3t^2\text{ and } 16t^2[/tex] have [tex]16t^2[/tex] are the larger value, hence [tex]s_e < s_p[/tex].

So, difference between the height obtained:

[tex]s_p - s_e = 79t - 3t^2 - (79t - 16t^2)\\\Rightarrow 79t -3t^2 - 79t + 16t^2\\\Rightarrow 13t^2[/tex]

So, [tex]13t^2[/tex] feet higher the stone will travel on the other plant than on Earth.

Not necessarily, the more correct definition is opposite reciprocal slopes.

The example used is how horizontal and vertical lines are parallel. Horizontal lines have a slope of 0, also written as 0/1. However, vertical lines have an undefined slope, which isn't necessarily negative. It has a slope of 1/0, which is undefined. In this case, the reciprocal isn't negative.

In all other cases (1 and -1, 2 and -1/2, etc.) yes, the perpendicular pairs are negative and reciprocal.

Answer:

$61.12

Step-by-step explanation:

Price of the Video game = $69.99

Discount = 18%

Discount price = 18% of $69.99

                         = $69.99*18/100

                         = $12.6

Price after Discount = Price - Discount price

                                  = $69.99 - $12.6

                                  = $57.39

Sales tax = 6.5% applied to the discounted price

                = 6.5% of $57.39

sales tax in dollars = $57.39 * 6.5/100

                               = $3.73

The amount he pays for the game = $57.39 + $3.73

                                                          = $61.12

Answer:

Step-by-step explanation:

Hello!

The objective is to  compare the VMT of mid western households and southwestern households. For this two independent random samples of households from both areas and their VMT were recorded:

Be

X₁: VMT of a mid western household

Midwest

16.2 , 14.6 , 11.2 , 24.4 , 9.4 12.9 , 18.6 , 16.6 , 20.3 ,15.1 , 17.3 , 10.8 , 16.6 , 20.9 , 18.3

n₁= 15

∑X₁= 243.20

∑X₁²= 4175.98

X[bar]₁= 16.21

S₁²= 16.64

S₁= 4.08

X₂: VMT of a southwestern household

22.2, 19.2 , 9.3 , 24.6 ,20.2 , 15.8, 18.0 , 12.2 , 20.1 , 16.0 , 17.5 , 18.2 , 22.8 , 11.5

n₂= 14

∑X₂= 247.60

∑X₂²= 4633.24

X[bar]₂= 17.69

S₂²= 19.56

S₂= 4.42

The parameters of study are the population means, if the claim is that the VMT of households is different in both areas, then you'd expect the population means to be different too.

The hypotheses are:

H₀: μ₁ = μ₂

H₁: μ₁ ≠ μ₂

α: 0.05

Assuming both populations are normal and since both population variances are equal the test to apply is an independent samples t test pooled variance:

[tex]t= \frac{(X[bar]_1-X[bar]2)-(Mu_1-Mu_2)}{Sa*\sqrt{\frac{1}{n_1} +\frac{1}{n_2} } } ~~t_{n_1+n_2-2}[/tex]

[tex]Sa^2= \frac{(n_1-1)S_1^2+(n_2-1)S_2^2}{n_1+n_2-2} = \frac{14*16.67+13*19.56}{15+14-2}= \frac{487.66}{27} = 18.06[/tex]

Sa= 4.249= 4.25

[tex]t_{H_0}= \frac{(16.21-17.69)-0}{4.25*\sqrt{\frac{1}{15} +\frac{1}{14} } }= -0.937= -0.94[/tex]

Critical value approach:

This test is two-tailed, this means that the rejection region is divided in two tails:

[tex]t_{n_1+n_2-2; \alpha /2}= t_{27; 0.025}= -2.052[/tex]

[tex]t_{n_1+n_2-2; 1-\alpha /2}= t_{27; 0.975}= 2.052[/tex]

The decision rule is:

If [tex]t_{H_0}[/tex] ≤ -2.052 or if [tex]t_{H_0}[/tex] ≥ 2.052, reject the null hypothesis.

If -2.052 < [tex]t_{H_0}[/tex] < 2.052, do not reject the null hypothesis.

The calculated value is within the "no rejection region" so the decision is to not reject the null hypothesis.

Using the p-value approach:

The p-value is the probability of obtaining a value as extreme as the calculated value of the statistic under the null hypothesis ([tex]t_{H_0}[/tex]). Just as the significance level, the p-value is two tailed, you can calculate it as:

P(t₂₇ ≤ -0.93) + P(t₂₇ ≥ 0.93)= P(t₂₇ ≤ -0.93) + (1 - P(t₂₇ < 0.93)= 0.1796 + ( 1 - 0.8204)= 0.1796*2= 0.3592

p-value= 0.3592

The p-value is always compared to the significance level, the decision rule for this approach is:

If the p-value ≤ α, reject the null hypothesis.

If the p-value > α, do not reject the null hypothesis.

The p-value is greater than α, so the decision is to not reject the null hypothesis.

At a 5% significance level, there is no significant evidence to reject the null hypothesis. You can conclude that the population means of the VMT for households of the Midwest  South ers households.

I hope this mhelps!

Answer:

A sample size of at least 531 is required.

Step-by-step explanation:

We are lacking the confidence level to solve this question, so i am going to use a 90% confidence level.

We have that to find our [tex]\alpha[/tex] level, that is the subtraction of 1 by the confidence interval divided by 2. So:

[tex]\alpha = \frac{1-0.9}{2} = 0.05[/tex]

Now, we have to find z in the Ztable as such z has a pvalue of [tex]1-\alpha[/tex].

So it is z with a pvalue of [tex]1-0.05 = 0.95[/tex], so [tex]z = 1.645[/tex]

Now, find the margin of error M as such

[tex]M = z*\frac{\sigma}{\sqrt{n}}[/tex]

In which [tex]\sigma[/tex] is the standard deviation of the population and n is the size of the sample.

Find the required sample size for the new study.

A sample size of at least n is required.

n is found when [tex]M = 0.05[/tex]

We have that [tex]\sigma = 0.7[/tex]

So

[tex]M = z*\frac{\sigma}{\sqrt{n}}[/tex]

[tex]0.05 = 1.645*\frac{0.7}{\sqrt{n}}[/tex]

[tex]0.05\sqrt{n} = 1.645*0.7[/tex]

[tex]\sqrt{n} = \frac{1.645*0.7}{0.05}[/tex]

[tex](\sqrt{n})^{2} = (\frac{1.645*0.7}{0.05})^{2}[/tex]

[tex]n = 530.4[/tex]

Rounding up

A sample size of at least 531 is required.