Answer:
And for this case since the confidence interval contains the value 0 we don't have significant evidence that we have a net change in the levels
Step-by-step explanation:
For this case we have the following info given:
represent the sample size
represent the sample mean
represent the sample deviation
We can calculate the confidence interval for the mean with the following formula:
The confidence level is 0.90 then the significance level would be 
and the degrees of freedom are given by:
And the critical value for this case would be:
And replacing we got:
And for this case since the confidence interval contains the value 0 we don't have significant evidence that we have a net change or efectiveness in the levels
Which one?????????????????
Using the normal distribution, it is found that 63.18% of the area under the curve of the standard normal distribution is between z = − 0.9 z = - 0.9.
<h3>Normal Probability Distribution</h3>
The z-score of a measure X of a normally distributed variable with mean 
and standard deviation 
is given by:
- The z-score measures how many standard deviations the measure is above or below the mean.
- Looking at the z-score table, the p-value associated with this z-score is found, which is the percentile of X.
The area within 0.9 standard deviations of the mean is the <u>p-value of Z = 0.9(0.8159) subtracted by the p-value of Z = -0.9(0.1841)</u>, hence:
0.8159 - 0.1841 = 0.6318 = 63.18%.
More can be learned about the normal distribution at brainly.com/question/4079902
#SPJ1
Answer:
Reflection
Step-by-step explanation:
Because reflecting yourself in a mirror means pre image to image
