Hypothesis Testing

APP6JMaloney       problems 2. 4, 6, 10, 18, 22, 24

2 ) The value of the z score un a hypothesis test is influenced by a variety of factors.
Assuming that all the other variables are held constant, explain how the value
of Z is influenced by each of the following?
Z= M - u / SD
a) Increasing the difference between the sample mean and the original.
The z score represents the distance of each X or score from the mean.
If the distance between the sample mean and the population mean the   z score will
increase.
b) Increasing the population standard deviation.
The standard deviation is the factor that is used to divide by in the equation. the bigger the SD,
then the smaller the z score.
c) Increasing the number of scores in the sample.
Should bring the samples mean closer to the population mean so z score will get smaller.

4) If the alpha level is changed from .05 to .01
a) what happens to the boundaries for the critical region?
It reduces the power of the test to prove the hypothesis.
You increase the chance of rejecting a true H
b) what happens to the probability of a type 1 error?
Type 1 error is falsely reporting a hypothesis,
Where you increase the chance that you will reject a true null hypothesis.

6) A researcher is investigating the effectiveness of a new study skills training program for elementary
school childreen. A sample of n=25 third grade children is selected to participate in the program
and each child is given a standardizrd achievement test at the end of year. For the regular
population of third grade children, scores on the test form a normal distribution with a
mean u = 150, and a standard deviation q = 25. The mean for the sample is M = 158.
a) Identify the independent and the dependent variables in the study
Independent = third grade child
Dependent = Score on test
b) Assuming a two-tailed test, state null hypothesis that includes the independent & dependent variable.
Ho: After the program... [continues]

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