Question

we use the t distribution for the statistical inference of the population mean when the underlying population standard deviation is not known. Under the assumption that the population is normally distributed, find tα/2,df for the following scenarios. Use Table 2. (Round your answers to 3 decimal places.) tα/2,df
a. A 90% confidence level and a sample of 28 observations.
b. A 95% confidence level and a sample of 28 observations.
c. A 90% confidence level and a sample of 15 observations.
d. A 95% confidence level and a sample of 15 observations

Answer 1

Answer:

Step-by-step explanation:

Since population std deviation is not  known, we use t critical value for testing of hypothesis.

a) 90% conf level when n =28

df = 27, t critical = 1.706

b) 95% 28

df =27 and t critical = 2.052

c) 90% and 15

df =14 and t critical = 1.761

d) 95% and n =15

df =14:   t critical = 2.145