Statistics and Probability Answers

Consider the population of the values (1,2,3,4).

A. List all the possible samples of size 2 with replacement

B. Compute the mean of each sample.

C. Identify the probability of each sample.

D. Compute the mean of the sampling distribution of the means.

A random variable X has μ=12.00 and σ=3.20. Find the corresponding z- score for X=8.

How many possible samples n=2 can be drawn from a population of size 14?

How many possible samples n=2 can be drawn from a population of size 14?

3. A psychologist believes that it will take at least an hour for certain disturbed

children to learn a task. A random sample of 30 of these children results in a

mean of 50 minutes to learn the task. Should the psychologist modify her belief

at the 0.01 level if the population standard deviation can be assumed to be 15

minutes?

2. A light-bulb manufacturer regularly advertises that his bulbs last 900 hours

with a standard deviation of 75 hours. A random sample is chosen before each

campaign to make sure that the claim is correct. If one such sample of 20 bulbs

show a mean of 925 hours, can the advertising claim be considered an

underestimate at the 0.05 level of significance?

1. According to the norms established for a history test, grade eight students

should have an average 81.7 with a standard deviation of 8.5. If 100 randomly

selected grade eight students from a certain school district average 79.6 in this

test, can we conclude at the 0.05 level of significance that grade eight students

from this school district can be expected to average less than the norm of 81.7?

DETERMINE THE NUMBER OF SETS OF ALL POSSIBLE RANDOM SAMPLES THAT CAN BE DRAWN FROM THE GIVEN POPULATION BY USING THE FORMULA, NCn.

N = 10, n = 3

IDENTIFY WHICH SAMPLING METHOD IS APPLIED. A SAMPLE OF 15 MICE ARE SELECTED AT RANDOM FROM A SET OF 50 MICE TO TEST THE EFFECT OF A CERTAIN MEDICINE.

DETERMINE THE NUMBER OF SETS OF ALL POSSIBLE RANDOM SAMPLES THAT CAN BE DRAWN FROM THE GIVEN POPULATION BY USING THE FORMULA, _NC_n.N = 5, n = 3.