Question

Basic Computation: Testing M1 2 M2 A random sample of 49 measurements from a population with population standard deviation 3 had a sample mean of 10. An independent random sample of 64 measurements from a second population with population standard deviation 4 had a sample mean of 12. Test the claim that the population means are different. Use level of significance 0.01. (a) Check Requirements What distribution does the sample test statistic follow

Answer 1

Answer:

The sample statistics follows a standard normal distribution since the sample size are large enough.

Step-by-step explanation:

Given that:

First population:

Sample size $n_1$ = 49

Population standard deviation $\sigma_1$  = 3

Sample mean $\overline x _1$= 10

Second population:

Sample size $n_2$ = 64

Population standard deviation $\sigma_2$= 4

Sample mean $\overline x_2$= 12

The sample statistics follows a standard normal distribution since the sample size are large enough.

The null and alternative hypotheses can be computed as:

$\mathbf{H_o:\mu_1=\mu_2}$

$\mathbf{H_1:\mu_1\ne\mu_2}$

Level of significance  = 0.01

Using the  Z-test statistics;

$Z = \dfrac{\overline x_1 - \overline x_2}{\sqrt{\dfrac{\sigma_1^2}{n_1} + \dfrac{\sigma_2^2}{n_2}}}$

$Z = \dfrac{10- 12}{\sqrt{\dfrac{3^2}{49} + \dfrac{4^2}{64}}}$

$Z = \dfrac{-2}{\sqrt{\dfrac{9}{49} + \dfrac{16}{64}}}$

$Z = \dfrac{-2}{\sqrt{0.18367 +0.25}}$

$Z = \dfrac{-2}{\sqrt{0.43367}}$

$Z = \dfrac{-2}{0.658536}$

Z = - 3.037

Z $\simeq$ - 3.04

The P-value = 2P (z < -3.04)

From the z tables

= 2 × (0.00118)

= 0.00236

Thus, since P-value is less than the level of significance, we fail to reject the null hypotheses $H_o$