If one box has a surface area of 240 inches what is the surface area of 5 boxes??
2 answers:
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Answer:
They will each have saved $70.
Jessica is saving at a faster rate than Raphael.
The rate at which Jessica is adding to her savings is $4 per week more than the rate at which Raphael is adding to his savings.
Step-by-step explanation:
The formula for Jessica’s savings is
y = 10x + 20
She is saving at the rate of $10/wk .
From Raphael’s table, he started with $40 and is saving at the rate of $6/wk.
The formula for Raphael’s savings is
y = 6x +40
When the two savings are equal
10x + 20 = 6x + 40 Subtract 20 from each side
10x = 6x + 20 Subtract 6x from each side
4x = 20 Divide each side by 4
x = 5
Their savings will be equal after five weeks.
=====
After five weeks , Jessica will have saved
y = 10×5 + 20
y = 50 + 20
y = $70
Raphael has also saved $70.
=====
Jessica is saving at a faster rate than Raphael.
She is saving at the rate of $10/wk, while he is saving at the rate of $6/wk.
The rate at which Jessica is adding to her savings is $4/wk more than the rate at which Raphael is adding to his savings.
The red line in the graph shows that Jessica starts with $20. After five weeks, she has caught up to Raphael, who also has $70 after five weeks.
Answer:
a. We fail to reject the hypothesis that the average credit score for an adult in Virginia is different from the average credit score for an adult in North Carolina at the significance level of 0.05.
b. The 95% confidence interval for the true difference of means is -2.2468 and 36.2468. There is a probability of 95% that the true difference of means is between -2.2468 and 36.2468. This confidence interval contains the number 0, this is consistent with the results we got in a. Because we fail to reject the hypothesis that the average credit score for an adult in Virginia is different from the average credit score for an adult in North Carolina at the significance level of 0.05.
Step-by-step explanation:
Let be the true difference between the average credit score for an adult in Virginia and the average credit score for an adult in North Carolina. We have the large sample sizes
and
, the unbiased point estimate for
is
, i.e., 699-682 = 17.
The standard error is given by , i.e.,
= 9.8198.
a. We want to test vs
(two-tailed alternative). The rejection region is given by RR = {z | z < -1.96 or z > 1.96} where -1.96 and 1.96 are the 2.5th and 97.5th quantiles of the standard normal distribution respectively. The test statistic is
and the observed value is
. Because 1.7312 does not fall inside RR, we fail to reject the null hypothesis.
b. The endpoints for a 95% confidence interval for is given by
, i.e.,
where
is the 2.5th quantile of the standard normal distribution, i.e., -1.96, so, we have 17-(1.96)(9.8198) and 17+(1.96)(9.8198), i.e., -2.2468 and 36.2468. There is a probability of 95% that the true difference of means
is between -2.2468 and 36.2468. This confidence interval contains the number 0, this is consistent with the results we got in a. Because we fail to reject the hypothesis that the average credit score for an adult in Virginia is different from the average credit score for an adult in North Carolina at the significance level of 0.05.