A population has a mean of = 50 and a standard deviation of = 12.

For samples of size n = 16, what is

. the mean (expected value) and

the standard deviation (standard error) for the distribution of sample means?

2) A population has a mean of = 100 and a standard deviation of = 16.

For samples of size n = 16, what is

the mean (expected value) and

the standard deviation (standard error) for the distribution of sample means?

3) As sample size increases, the value of the standard error also increases

True

False

4) For a population has a mean of = 16 and a standard deviation of = 8 find the z-score corresponding to a sample mean of M= 20 for each of the following sample sizes.

n=4

5) For a population has a mean of = 16 and a standard deviation of = 8 find the z-score corresponding to a sample mean of M= 18 for each of the following sample sizes.

n=4

6) What is the probability of obtaining a sample mean greater than M=70 for a random sample of n= 16 scores selected from a normal population with a mean of =60 and a standard deviation of =20?

7) What is the probability of obtaining a sample mean greater than M=50 for a random sample of n= 4 scores selected from a normal population with a mean of =60 and a standard deviation of =20?

8a) For a population that has a standard deviation of 20, determine the standard deviation of the distribution of means for samples of size of 4

8b) For a population that has a standard deviation of 20, determine the standard deviation of the distribution of means for samples of size 9.

9) A psychologist is interested in the conditions that affect the number of dreams per month that people report in which they are alone. In the general population the number of such dreams per month follows a normal curve, with = 5 and = 4. The psychologist studies 36 individuals and found that their mean number of alone dreams is 8. What is the Z score for this groups mean in the distribution of sample means?

10) A psychologist is interested in the score of college students on the GRE. In the general population the number of correct response follows a normal curve, with = 15 and = 4. The psychologist studies 4 individuals and found that their mean number of correct response at for CCNY is 18. What is the Z score for this groups mean in the distribution of sample means?

11) A industrial psychologist is interested in the number of accidents that happen at the Honda factory. In the general population the number of correct accident follows a normal curve, with = 5 and =2. The psychologist studies 30 factors and found that their mean number of accidents were 4.5. What is the Z score for this groups mean in the distribution of sample means?

12) (For this question, consider z values greater than 3 as atypical).

A population of scores forms a normal distribution with a mean of = 80 and =20. Is it atypical to get a mean of 84 in a sample of n=4 scores?

A) Yes

B) No

13) (For this question, consider z values greater than 3 as atypical).

A population of scores forms a normal distribution with a mean of = .30 and =.08. Is it typical to get a mean of .33 in a sample of n=16 scores?

A)yes

B) No

14) A population of gifted IQ scores forms a normal distribution with a mean of = 120 and =10.

For samples of n =16, what proportion of the samples will have means between 115 and 120?

15) A sample of 36 dieters are in a weight lost program. People who do program typically loss 40 lbs of weight (with a standard deviation of 12). This sample of dieters lost 45 lbs. Obtain the z score for this sample.