A contractor claims the mean value of his compression test is 6500 psi and has astandard deviation of 500 psi. You attempt to check this by taking 8 sample measurements and findyour average is 5900 psi. If your levelof significance is 0.01, would you believe the means are the same

This value of 5675 psi by the contractor is safer than 5487.5 psi as it is of lesser value.

Step-by-step explanation:

The following parameters are given from the question above. These information is used in solving this problem.

=> The mean value of his compression test = 6500 psi, the standard deviation = 500 psi, the average of the mean = 5900 psi and the number of sample measurements = 8.

The first thing to do right now is to determine the characteristic strength, this can be calculated as below:

Characteristic strength= average of the mean - (1.65/2) × standard deviation.

Characteristic strength = 5900 - (0.825) × 500 = 5487.5 psi.

The next thing to do is to Determine the target mean strength.

Target mean strength = 5487.5 psi + 1.65 × 500 = 6312.5 psi.

The above is from taking samples from 8 samples.

Now, let's consider the characteristic strength by the contractor.

Characteristics strength = 6500 - 165 × 500 = 5675 psi.

This value of 5675 psi by the contractor is safer than 5487.5 psi as it is of lesser value.

let x be the money she spent so that she can earn the free t-shirt.

since, she already spent $112.49

⇒

also, as per the statement: jennifer must spend $250 or more in order to qualify for a free t-shirt at the store.

then,

we have an inequality i.,e

subtract 112.49 from both sides we get;

therefore, $137. 51 more money does jennifer need to spend so that she can earn the free t-shirt

we can't see all full 4 options, but if this is the full option, than the very left one is correct:

-2/5 * -3 3/4

remake the question, adding a picture of all the question, or write down the full left and right answers.