Answer:
a: H0: µ = 7980, Ha: µ < 7980 (claim)
b: -3.162
c: P-value is 0.00576
d: 7821.61 < µ < 7978.39
Step-by-step explanation:
The given data for the situation is:
µ = 7980, σ = 80, x = 7900, n = 10
The hypothesis are
H0: µ = 7980
Ha: µ < 7980 (claim)
This is a left tailed test, with a significance level of 0.01, so the critical value for the situation is: t < -2.821
See the attached photo 1 for the calculation of the test statistic...
Use a chart, software or online calculator to find the p-value of the test statistic
See attached photo 2 for the construction of the confidence interval