In: Statistics and Probability
We use the t distribution to construct a confidence interval for 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. (You may find it useful to reference the t table. Round your answers to 3 decimal places.)
tα/2,df | ||
a. | A 90% confidence level and a sample of 23 observations. | |
b. | A 95% confidence level and a sample of 23 observations. | |
c. | A 90% confidence level and a sample of 21 observations. | |
d. | A 95% confidence level and a sample of 21 observations. | |
(a) n = 23
Degrees of freedom = df = n - 1 = 23 - 1 = 22
At 90% confidence level the t is ,
(b) n = 23
Degrees of freedom = df = n - 1 = 23 - 1 = 22
a ) At 95% confidence level the t is ,
( c) n = 21
Degrees of freedom = df = n - 1 = 21 - 1 = 20
At 90% confidence level the t is ,
(d) n = 21
Degrees of freedom = df = n - 1 = 21 - 1 = 20
a ) At 95% confidence level the t is ,