Question

Can someone check my work

Answer 1

1. Suppose that 44% of all Americans approve of the job our President is doing. The most recent Gallup poll consisted of a random sample of 1400 American adults.

A) what is the mean of the sampling distribution?
B) what is the standard deviation of the sampling distribution dont forget to justify the use of the formula


A) N*P= .44 * 1400=616
B) std (N*P*Q)= (1400*(.44)*(1-.44)=18.573


2)
The distribution of salaries in a company is skewed to the right. That is, most employees make a small amount of money while a few executives earn much higher salaries.

a) What would a sampling distribution of sample size 3 look like?
b) What would a sampling distribution of sample size 10 look like?
c) What would a sampling distribution of sample size 50 look like?

A) still skewed right

B) Beginning to start to look normal, but not perfect

C) normal shape

3)
The average weight of a chicken egg is 2.25 ounces with a standard deviation of 0.2 ounces. You take a random sample of a dozen eggs.

a) What are the mean and standard deviation of the sampling distribution of sample size 12?
b) What is the probability that the mean weight of the eggs in the sample will be less than 2.2 ounces?


a) mean = 2.25, standard deviation = 0.2 / sqrt(11)

b) Z = (2.20 - 2.25) / 0.20 = -0.25.= 45%

4)

In a card game (using a standard deck of cards), you pay $5 to draw a single card. If you draw an Ace, you win $20. If you draw a face card, you win $10. If you draw a 2, you win $5.

a) Fill in the probability distribution below:

X 5 10 20
P(X)


A) P(x)=5: .096 10: 2.404 20: 2.788

Answer 2

@ganeshie8

Answer 3

You'll want to confirm this with a text book or something (it's been awhile since I've done population statistics), but I believe the standard deviation is calculated by:

\[\sigma = \sqrt{\frac{PQ}{N}}\]

Answer 4

#1 and #2 are looking good

Answer 5

for #3 :

3)
The average weight of a chicken egg is 2.25 ounces with a standard deviation of 0.2 ounces. You take a random sample of a dozen eggs.

a) What are the mean and standard deviation of the sampling distribution of sample size 12?
b) What is the probability that the mean weight of the eggs in the sample will be less than 2.2 ounces?


a) mean = 2.25, standard deviation = 0.2 / sqrt(\(\color{Red}{12}\))

b) Z = (2.20 - 2.25) / \((\color{red}{0.20/\sqrt{12}})\) = ??

Answer 6

^^You must use standard deviation of "sampling distribution" right ?