Question

Suppose we are testing the null hypothesis Ho: mu = 20 and the alternative Ha: mu does not equal 20, for a normal population with sigma = 5. A random sample of 25 observations are drawn from the population, and we find the sample mean of these observations is X bar = 17.6. The P-value is closest to (A) 0.0164 (B) 0.0668 (C) 0.1336 (D) 0.0082

Answer 1

Since , the population standard deviation is known.

Therefore , use normal distribution

Since , the test is two-tailed test.

The test statistic is ,

The p-value is ,

p-value=

; From standard normal distribution table