Answer:
Step-by-step explanation:
Use the formula to find the z-score, then go to the table that will give you the probability that the value is less than this z-score.
The probability that the value lies to the left of 1 on a standard bell curve is 84.1345%, or 84%, the third choice down.
Answer:
70 questions
Step-by-step explanation:
You can make a proportion.
Multiply across:
7x=490
Divide by 7:
x=70
<u>Final answer</u>
70 questions
Answer: (30.49 years, 42.31 years)
Step-by-step explanation:
The formula to find the confidence interval is given by :-
, where = Sample mean
z* = Critical value.
= Population standard deviation.
n= Sample size.
As per given , we have
n= 40
We know that the critical value for 99% confidence interval : z* = 2.576 (By z-table)
A 99 percent confidence interval for µ, the true mean age of guests will be :
∴ a 99 percent confidence interval for µ, the true mean age of guests = (30.49 years, 42.31 years)