Answer:
Step-by-step explanation:
12/30 = 0.4
percent is rquivalent to 12/30 : 0.4×100 =40
<span>Multiplication Property of –1</span>
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.= 
-1/4
This will remain its absolute value