Answer: a. 69.72 ± 1.37
Step-by-step explanation:
We want to determine a 90% confidence interval for the mean height (in inches) of adult men in the United States.
Number of sample, n = 25
Mean, u = 69.72 inches
Standard deviation, s = 4.15
For a confidence level of 90%, the corresponding z value is 1.645. This is determined from the normal distribution table.
We will apply the formula
Confidence interval
= mean ± z × standard deviation/√n
It becomes
69.72 ± 1.645 × 4.15/√25
= 69.72 ± 1.645 × 0.83
= 69.72 ± 1.37
The lower end of the confidence interval is 69.72 - 1.37 = 68.35
The upper end of the confidence interval is 69.72 + 1.37 = 71.09
Answer:he must save an average of $150 or more in each of the remaining 8 months.
Step-by-step explanation:
Mr. Helsley wishes to save at least $1500 in 12 months. If he saved $300 during the first 4 months, then the amount left would be
≥ 1500 - 300
Let x represent the least possible average amount that he must save in each of the remaining 8 months. This means that the total amount that he would save in the last 8 months would be 8x. Therefore,
300 + 8x ≥ 1500
8x ≥ 1500 - 300
8x ≥ 1200
x ≥1200/8
x ≥ 150
Your answer should be 19>n+3
Answer:
D
Step-by-step explanation:
Given
4x + 8.2 ≤ 32.2 ( subtract 8.2 from both sides )
4x ≤ 24 ( divide both sides by 4 )
x ≤ 6 → D