Answer:
there are two ways we can solve this problem the first way is in x-form and the second way is in y-form I will give you the answer for each of the ways.
Step-by-step explanation:
x-form: x=37-3y
y-form: y=37/3 - x/3
hope this helps if this was not the way you wanted me to solve it please let me know and I will do it the way you want me to do it.
I think it would be a 1 in 6 chance for 1 time so I would assume for 2 times it would be a 2 in 12 chance (1/6, 2/12)
Answer:
2.5%
Step-by-step explanation:
% = (faulty batteries / total batteries) x 100
= (3/120) x 100
= 0.025 x 100
= 2.5
X+5−5=8−5 subtract -5 on each side
x=3
Answer:
a) 8.5
b) between 7.7 and 9.3.
c)Both using a sample of size 400 (instead of 81) and using a 90% level of confidence (instead of 95%) are correct.
(e) 144
Step-by-step explanation:
Explanation for a)
The point estimate for the population mean μ is the sample mean, x ¯ . In this case, to estimate the mean number of weekly hours of home-computer use among the population of U.S. adults, we used the sample mean obtained from the sample, therefore x ¯ = 8.5.
Explanation for b)
The 95% confidence interval for the mean, μ, is x ¯ ± 2 ⋅ σ n = 8.5 ± 2 ⋅ 3.6 81 = 8.5 ± . 8 = ( 7.7 , 9.3 ) .
Explanation for c)
In general, a more concise (narrower) confidence interval can be achieved in one of two ways: sacrificing on the level of confidence (i.e. selecting a lower level of confidence) or increasing the sample size
Explanation for d)
We would like our confidence interval to be a 95% confidence interval (implying that z* = 2) and the confidence interval length should be 1.2, therefore the margin of error (m) = 1.2 / 2 = .6. The sample size we need in order to obtain this is: 144.
