n engineer designed a valve that will regulate water pressure on an automobile engine. The engineer designed the valve such that it would produce a mean pressure of 5.4 pounds/square inch. It is believed that the valve performs above the specifications. The valve was tested on 9 engines and the mean pressure was 5.7 pounds/square inch with a variance of 0.81. A level of significance of 0.025 will be used. Assume the population distribution is approximately normal. Make the decision to reject or fail to reject the null hypothesis.

The calculated t- value =  1.11 > 2.89 at 0.025 level of significance

Null hypothesis is rejected

The engineer designed the valve such that it would produce a mean pressure is not equal to  5.4

Step-by-step explanation:

Step(i):-

Given mean of the Population (μ) = 5.4

Given sample size 'n' = 9

Mean of the sample (x⁻) = 5.7

Standard deviation of the sample (s) = 0.81

Step(ii):-

Null Hypothesis: H₀:  The engineer designed the valve such that it would produce a mean pressure of 5.4

H₀: μ = 5.4

Alternative Hypothesis : H₁:  μ ≠ 5.4

Level of significance = 0.025

Test statistic

         t = 1.11

Degrees of freedom

ν = n-1 = 9-1 =8

t₀.₀₁₅ , ₈  = 2.89

The calculated t- value =  1.11 > 2.89 at 0.025 level of significance

Null hypothesis is rejected

The engineer designed the valve such that it would produce a mean pressure is not equal to  5.4

part a

in a city ice cream is mostly only bought when the temperature is very high as ice cream cools down our

so we can derive the conclusion that as the temperature increases the number of ice creams sold also increases

part b

y intercept is 5

slope is 2

happy to

pls mark as brainliest