Consider the following hypothesis test :

$H_0: \mu ≤ 30$

$H_a : \mu > 30 $

A sample of 49 provided a sample mean of 31.5. The population standard deviation is 3. The value of the test statistic is :

3.5

The correct answer is Option (1) → 3.5

The z-score formula is,

$z=\frac{\bar x-μ}{σ/\sqrt{n}}$

$=\frac{31.5-30.0}{3/\sqrt{49}}=\frac{1.5}{0.4286}$

$≃3.5$