An 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 4.1 pounds/square inch. it is believed that the valve performs above the specifications. the valve was tested on 120 engines and the mean pressure was 4.3 pounds/square inch. assume the variance is known to be 0.64. a level of significance of 0.05 will be used. make a decision to reject or fail to reject the null hypothesis. make a decision.

We reject the null hypothesis at the significance level of 0.05.

Step-by-step explanation:

vs (upper-tail alternative)

We have , and n = 120. We have a large sample and our test statistic is

which is normal standard approximately. We have observed

.

We should use the significance level . The 95th quantile of the standard normal distribution is and the rejection region is given by {z > 1.6449}. Because the observed value 2.7386 is greater than 1.6449, we reject the null hypothesis at the significance level of 0.05.

a. 12.5 kg

step-by-step explanation:

f = ma

so

m = f/a = (2500 n)/(200 m/s²) = 12.5 kg

1 n = 1 kg·m/s²

step-by-step explanation:

step 1: solve one of the equations for one of the variables. let's solve the first equation for y:

step 2: substitute that equation into the other equation, and solve for x.

step 3: substitute x = 4 x = 4 x=4 into one of the original equations, and solve for y.