Question

Plant	Sample size	Sample mean	Sample sd
A	50	50.3	0.2
B	50	50.7	0.3

(a) (7 points) Is there evidence, at 5% significance level, to show that the mean diameter of these two plants are different? Write down the hypotheses, test statistic, P-value and your conclusion.

Answer 1

The test statistic is

  

P-value = 2 * P(Z < -7.84)

= 2 * 0 = 0

Since the P-value is less than the significance level (0 < 0.05), so we should reject the null hypothesis.

At 0.05 significance level, there is sufficient evidence to conclude that the mean diameter of these two plants are different.