Answer:
Part a
Null hypothesis: [tex] \mu = 69.3[/tex]
Alternative hypothesis: [tex]\mu \neq 69.3[/tex]
Part b
[tex] z = \frac{69.8- 69.3}{\frac{11.2}{\sqrt{140}}}= 0.528[/tex]
Step-by-step explanation:
For this case we have the following info given :
[tex] \bar X = 69.8[/tex] the sample mean
[tex] n= 140[/tex] represent the sample size
[tex] s = 11.2[/tex] represent the standard deviation
Part a
And we want to test if the true mean is equal to 69.3 so then the system of hypothesis:
Null hypothesis: [tex] \mu = 69.3[/tex]
Alternative hypothesis: [tex]\mu \neq 69.3[/tex]
Part b: Find the statistic
The statistic is given by:
[tex] z= \frac{\bar X - \mu}{\frac{\sigma}{\sqrt{n}}}[/tex]
And replacing the info we got:
[tex] z = \frac{69.8- 69.3}{\frac{11.2}{\sqrt{140}}}= 0.528[/tex]