Answer:
go study yourself
Step-by-step explanation:
Answer:
The confidence interval becomes wider.
Step-by-step explanation:
The general form of a confidence interval is:

The critical value is based on the confidence level.
The confidence level is the probability that the true parameter value falls within a specific interval. The basic and most used confidence levels are 90%, 95% and 99%.
The confidence interval is directly proportional to the confidence interval.
Confidence Interval ∝ Confidence Level
On increasing the confidence level the confidence level widens. And on decreasing the confidence level the confidence level gets narrower.
Thus, when Gina changes the confidence interval to 99% the confidence interval becomes wider.
9 times 4 = 4 times (9) because it equals to itself.
9 time 4 is 36
4 times 9 is 36
Answer:C. (77.29, 85.71)
Step-by-step explanation:
We want to determine a 95% confidence interval for the mean test score of randomly selected students.
Number of sample, n = 25
Mean, u = 81.5
Standard deviation, s = 10.2
For a confidence level of 95%, the corresponding z value is 1.96. This is determined from the normal distribution table.
We will apply the formula
Confidence interval
= mean +/- z ×standard deviation/√n
It becomes
81.5 +/- 1.96 × 10.2/√25
= 81.5 +/- 1.96 × 2.04
= 81.5 +/- 3.9984
The lower end of the confidence interval is 81.5 - 3.9984 =77.5016
The upper end of the confidence interval is 81.5 + 3.9984 =85.4984
Therefore, the correct option is
C. (77.29, 85.71)