Answer:
Step-by-step explanation:
Given: Sample size: n = 41
Sample mean degrees
Population standard deviation degrees
Confidence level (c) = 80% =0.80
Significance level (a) = 1- c = 1-0.80 = 0.20
z-score for 80% confidence level : z = 1.2816 [from z-table]
Confidence level for population mean :-
Hence, 80% confidence interval for the temperatures in the freezer
Answer:
The null hypothesis is .
The alternative hypothesis is
Step-by-step explanation:
Suppose that a recent article stated that the mean time spent in jail by a first-time convicted burglar is 2.5 years.
At the null hypothesis, we test if the mean is of 2.5 years, that is:
A study was then done to see if the mean time has increased in the new century.
At the alternative hypothesis, we test if the mean has increased, that is, if it is above 2.5 years. So