MATHEMATICS COLLEGE

A preliminary sample of holiday shoppers revealed that the standard deviation of the amount of money they are planning to spend on gifts during the coming holiday season is $80. How many holiday shoppers should be sampled in order to estimate the average amount of money spent on gifts by all holiday shoppers with a margin of error of $7 and with a 99% confidence

Answers

Answer 1

Answer:

Answer:

$n=((2.58(80))/(7))^2 =869.407 \approx 870$

So the answer for this case would be n=870 rounded up to the nearest integer

Step-by-step explanation:

Information given

$\sigma = 80$ represent the deviation

ME = 7 represent the margin of error

Solution

The margin of error is given by this formula:

$ME=z_(\alpha/2)(\sigma)/(√(n))$ (a)

And on this case we have that ME =7 and we are interested in order to find the value of n, if we solve n from equation (a) we got:

$n=((z_(\alpha/2) \sigma)/(ME))^2$ (b)

The critical value for 99% of confidence interval now can be founded using the normal distribution. The significance level would be $\alpha=0.01$ and $\alpha/2 =0.05$ . The critical value would be $z_(\alpha/2)=2.58$ , replacing into formula (b) we got:

$n=((2.58(80))/(7))^2 =869.407 \approx 870$

So the answer for this case would be n=870 rounded up to the nearest integer

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Answers

Was my answer correct...!?

Find the unit rate.3
1
4
gallon for every
mile
10
The unit rate is
gallon :
mile.

Answers

Answer:

22/40

Step-by-step explanation:

find the equivalent ratio of 4 and 10 and it is 40 so the then you multiply 4 times 10 and 10 times 4 then you multiply 1x10 and 10x4 so now your new problem will be

10/40+12/40 which is 22/40=1 8/15

Rolling a 12 sided die find the odds in favor of rolling a 5
rolling a multiple of 3
rolling an odd number
rolling a number greater than 6

Find each probability of
P(5)
P(# less than 3)
P(odd)
P(13)

Answers

Answer:

1/12 , 1/3 , 1/2 , 1/2

Step-by-step explanation:

P(x) = favorable of x / total

plug in your conditions and you get the probablility

Answer:

1/12 for rolling a 5.

4/12 for multiples of 3. (3,6,9,12)

6/12 for rolling an odd number.(1,3,5,7,9,11)

6/12 for rolling a number greater than 6. (7,8,9,10,11,12)

Step-by-step explanation:

At the start of the day there was 129.75 in the till one hour later there is 145.40 how much did the shop take in a hour

Answers

At the start of the day, there was £129.75. Later, they made more money, so the £145.50. To find the amount of change, you just need to deduct the number 129.75 from 145.50.

145.50 - 129.75 = 15.75

The shop made £15.75 in one hour.

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Answers

Answer: All expect cos of theta=17/8

Step-by-step explanation: Fist, let find a equal cos equation. let use the idenitiy( $cos^(2)$ Ф+ $sin^(2)$ Ф=1. $cos^(2)$ +15/17^2=1, $cos^(2)$ =1-225/289. $cos^(2)$ =289/289-225/289. $cos^(2)$ =64/289. sqr root of $cos^(2)$ = 8/17.