Consider the following hypothesis test :
$H_0 : \mu ≤20$
$H_a : \mu > 20 $
A sample of 49 provided a sample mean of 19.40. The population standard deviation is 2. The value of the test statistic is :
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → -2.1
The z-score formula,
$z=\frac{\bar x-μ_0}{σ/\sqrt{n}}$
$=\frac{19.40-20}{2/\sqrt{49}}=\frac{-0.60}{0.2857}$
$≃-2.1$