Question

A random sample of 86 observations produced a mean x=25.8 and a standard deviation s=2.4.

a. Find a​ 95% confidence interval for μ.

b. Find a​ 90% confidence interval for μ.

c. Find a​ 99% confidence interval for μ.

a. The​ 95% confidence interval is​(Use integers or decimals for any numbers in the expression.(____,_____)

Round to two decimal places as​ needed.)

b.The​ 90% confidence interval is​(Use integers or decimals for any numbers in the expression(_______,_____). Round to two decimal places as​ needed.)

c, The​ 99% confidence interval is​(Use integers or decimals for any numbers in the expression.(____,_______)

,Round to two decimal places as​ needed.)

Answer 1

α= 0.1 given 90% an/-- 0.05 b)Level of significance: . Critical value: /2_ 1.663 From t table Standard error: = 0.259 Marginfror 0.430377 Lower limit : X-%2 二25.36962 Upper limitx+ta2 α/21-1-26.23038 The confidence interval is(25.37 26.23)