Ascrap metal dealer claims that the mean of his cash scales is "no more than $80," but an internal revenue service agent believes the dealer is untruthful. observing a sample of 20 cash customers, the agent finds the mean purchases to be $91, with a standard deviation of $21. assuming the population is approximately normally distributed, and using the 0.05 level of significance, what is the calculated value of test statistic? (specify your answer to the 3rd decimal.)

The p-value for this hypothesis test is P=0.015.

Step-by-step explanation:

In this case we have hypothesis test for the mean, with standard deviation of the population unknown.

The null hypothesis we want to test is

To work with this test we have a sample of size n=20, sample mean=91 and sample standard deviation=21.

First, we estimate the standard deviation of the population

Then, because we have an estimated standard deviation, we have to calculate the statistics t.

We can look up this value of t in a t-table to know the probability of this value, taking into account 19 degrees of freedom:

The p-value or the probability of P(t>2.342) is 0.01511.

This value P=0.0151 is compared to the significance level (0.05). Since the probability value (0.0151) is less than the significance level (0.05) the effect is statistically significant. Since the effect is significant, the null hypothesis is rejected.

median is the value separating the higher half of a data sample, a population or probablity distribution from the lower half.

step-by-step explanation:

say you have 3,8,7,3,1,9,8 order them from lowest to highest

if orderd it would be 1,3,3,7,8,8,9 now you take away from the lowest and the highest until you end up in the middle.

so you would remove the 1 and 9 leaving you with 5 digits remaining

when you've reached the middle that would be your answer so in this case the answer is 7

if there were two numbers left say 7 and 5 you'd and them together so 12 then divide by 2 witch would equal 6 so the answer would be 6

good luck on that project hoped i you at all