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
The answer is D.
In the expression, the fraction must be larger than 1/4, yet smaller than 7/8.
It can't be A because 1/5 is smaller than 1/4. See below.
1/5 = 4/20
1/4 = 5/20
It also can't be B because 8/9 is larger than 7/8. See below.
8/9 = 64/72
7/8 = 63/72
Lastly, the answer cannot be C because 2/10 is smaller than 1/4.
1/4 = 5/20
2/10 = 4/20
Answer D works because:
10/20 = 2/4 > 1/4
10/20 = 80/160 < 140/160
If we multiply the first equation by 2 we get
2x - 4y = 12
but the second equation is
2x - 4y = 10
2x - 4y can't have 2 different values so the are no solutions
Answer:
The metric system uses units such as meter, liter, and gram to measure length, liquid volume, and mass, just as the U.S. customary system uses feet, quarts, and ounces to measure these.
Answer:
2/21+6/7 = 20/21
Step-by-step explanation:
2/21+6/7
=2/21+(6*3/7*3)
=2/21+18/21
=20/21
Hope this helps! Comment any questions <3
