Answer: 37
Step-by-step explanation:
As per given description in the question, we have
Population standard deviation : 
Critical value for 98% confidence interval = 
Margin of error : E= 1 mile per gallon
Formula we use to find the sample size :

i.e. 

Therefore , the number of automobiles should be used in the test =37
The answer should be from 1 to 23
Answer:
15, 8, 13, 13
Step-by-step explanation:
(1) mean = Σx / n = 135 / 9 = 15
(2) range = highest value - lowest value = 21 - 13 = 8
(3) mode = 13 (most repeated value in data set)
(4) for 9 values in a data set, we have that (9 + 1) / 2 = 5th number
median = 13
X =-1+2c/3
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