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
2
Step-by-step explanation:
common ratio(r)=-3/4
a2÷a1=r
32/9÷-128/27=-3/4
therefore using the common ratio to find the fourth term is just by multiplying the third term -8/3 by the common ratio -3/4
which equals = 2
Answer:
It should be easy to complete.
Step-by-step explanation:
1/2
Answer:
There are 75 pencils and 25 pens.
Step-by-step explanation:
If Tom has three times as many pencils than pens then,
Pencils = 3(Pens)
If there are a total of 100 writing utensils then,
Pencils + Pens = 100
Substitute the word "pencils" in this equation to 3(Pens),
3(Pens) + Pens = 100
Now remember there is almost a 'hidden' one beside the word "Pens" so,
3Pens + 1Pens = 100
Add the two together,
4Pens = 100
Divide,
Pens = 25
Substitute 25 into the first equation,
Pencils = 3(25)
Pencils = 75
Thus, there are 75 pencils and 25 pens.
