Answer: 
Step-by-step explanation:
As per given , we have
n = 11

Since population standard deviation is missing, so we use t-test.
Critical t-value for 99% confidence :
[using two-tailed t-value table]
Confidence interval :

Hence, 99% confidence interval for the mean amount of time that students spend in the shower each day.= 
12.5 x 4... hope this helped!
Answer:
Step 1: Put the numbers in order. ...
Step 2: Find the median. ...
Step 3: Place parentheses around the numbers above and below the median. Not necessary statistically, but it makes Q1 and Q3 easier to spot. ...
Step 4: Find Q1 and Q3. ...
Step 5: Subtract Q1 from Q3 to find the interquartile range.
Step-by-step explanation:
u should do those step and i think u will find the answer
The answer is b. All numbers are natural numbers