ICA #9
1.
What is by definition:
a. H
0 : null hypothesis is a claim of “no difference in the population” b. H
A: alternative hypothesis claims H
0 is false
2.
What are the steps in Hypothesis Testing?
1.
Set up the null and alternative hypotheses 2.
Form a test statistic 3.
Calculate a p-value and compare it to a pre-defined value
4.
Decision: whether or not to reject the null hypothesis 3.
What are the types of errors?
-
Type 1 error -
Type 2 error 4.
What is the use/application of P-value?
If the null hypothesis were true, what is the probability of the observed test statistic
or one that is more extreme to occur 5.
In the late 1970s, the mean weight of the United States male population aged
between 20 and 29 years was 170 pounds, with a standard deviation of 40. In the 2000s, the average weight of a simple random sample of 64 men was 185 pounds. Is the average weight of men in the 2000s higher than the average weight of men in the 1970s? 1970s- 20 and 29 years- 170 lb, sd 40 2000s- 64 men 185lb •
Null Hypothesis (H0): The average weight of men in the 2000s is not higher than the average weight of men in the 1970s (μ2000s ≤ μ1970s).
•
Alternative Hypothesis (Ha): The average weight of men in the 2000s is higher than the average weight of men in the 1970s (μ2000s > μ1970s).
z = (185 - 170) / (40 / √64)
z = 15 / (40 / 8)
