<h2>
Answer : (2.67, 3.53)</h2><h2>
</h2>
Step to step explanation:
Confidence interval for mean, when population standard deviation is unknown:

, where
= sample mean
n= sample size
s= sample standard deviation
= Critical t-value for n-1 degrees of freedom
We assume the family size is normal distributed.
Given, n= 31 ,
, s= 1.42 ,

Critical t value for
and degree of 30 freedom
= 1.697 [By t-table]
The required confidence interval:

Hence, the 90% confidence interval for the estimate = (2.67, 3.53)
Answer:
24
Step-by-step explanation:
Let t represent the volume of the tank in gallons. Then we have ...
(1/8)t + 15 = (3/4)t . . . . . . . . . . . adding 15 gallons fills the tank to 3/4
15 = (6/8 -1/8)t = (5/8)t . . . . . . . subtract 1/8t
15(8/5) = (8/5)(5/8)t . . . . . . . . . multiply by 8/5 (the inverse of 5/8)
24 = t
The tank holds 24 gallons.
Triangle D
Because the Pythagorean Theorem is only used with a RIGHT triangle
I’m pretty sure it’s c if not then a