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 6.3 pounds/square inch. it is believed that the valve performs above the specifications. the valve was tested on 130 engines and the mean pressure was 6.5 pounds/square inch. assume the standard deviation is known to be 0.8. a level of significance of 0.02 will be used. determine the decision rule. enter the decision rule.

We conclude that the valve performs above the specifications.

Step-by-step explanation:

We are given the following in the question:

Population mean, μ = 6.3 pounds per square inch

Sample mean, = 6.5 pounds per square inch

Sample size, n = 130

Alpha, α = 0.02

Population standard deviation, σ = 0.8

First, we design the null and the alternate hypothesis

We use one-tailed z test to perform this hypothesis.

Formula:

Putting all the values, we have

Now,

Decision rule:

If the calculated statistic is greater than the the critical value, we reject the null hypothesis and if the calculated statistic is lower than the the critical value, we accept the null hypothesis

Since,  

We fail to accept the null hypothesis and reject the null hypothesis. We accept the alternate hypothesis.

Thus, we conclude that the valve performs above the specifications.

"it's not the heat, it's the humidity".   that's a partly valid phrase you may have heard in the summer, but it's actually both.   the heat index, also known as the apparent temperature, is what the temperature feels like to the human body when relative humidity is combined with the air temperature.   this has important considerations for the human body's comfort.   when the body gets too hot, it begins to perspire or sweat to cool itself off.   if the perspiration is not able to evaporate, the body cannot regulate its temperature.   evaporation is a cooling process.   when perspiration is evaporated off the body, it effectively reduces the body's temperature.   when the atmospheric moisture content (i.e. relative humidity) is high, the rate of perspiration from the body decreases.   in other words, the human body feels warmer in humid conditions.   the opposite is true when the relative humidity decreases because the rate of perspiration increases.   the body actually feels cooler in arid conditions.   there is direct relationship between the air temperature and relative humidity and the heat index, meaning as the air temperature and relative humidity increase (decrease), the heat index increases (decreases).

step-by-step explanation: