Question

A population is normally distributed. To test that its population mean is less than 70, we collect a random sample of size 27 with mean 68 and standard deviation 7. What is the value of the critical value at the level of significance 10%?

Select one:

a. None of the other answers is true.

b. 1.31

c. -1.48

d. -1.31

e. 1.48

Answer 1

Answer:

Given that,

A population is normally distributed.

To test that its population mean is less than 70, we collect a random sample of size 27 with mean 68 and standard deviation 7.

That is,

Mean ()=68

Sample Size (n)=27

Standard Deviation()=7

To find degree of freedom:

Degree of freedom (df)=n-1

=27-1

=26

Therefore, df=26

The value of the critical value at the level of significance 10%:

Given the level of significance=10%=0.10

The critical value for a left-tailed is tc=-1.31(From t table)

Therefore, Option(d) is correct.