TOGETHER , TWO PEOPLE EARN $28,000. ONE EARNS $2,000 MORE THAN THE OTHER. HOW MUCH IS SMALLER INCOME?
1 answer:
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Answer:
Critical value: T = 1.337
The 80% confidence interval for the mean repair cost for the stereos is between $45.991 and $86.689
Step-by-step explanation:
We have the standard deviation for the sample. So we use the t-distribution to solve this question.
The first step to solve this problem is finding how many degrees of freedom, we have. This is the sample size subtracted by 1. So
df = 17 - 1 = 16
80% confidence interval
Now, we have to find a value of T, which is found looking at the t table, with 16 degrees of freedom(y-axis) and a confidence level of . So we have T = 1.337, which is the critical value
The margin of error is:
M = T*s = 1.337*15.22 = 20.349
In which s is the standard deviation of the sample.
The lower end of the interval is the sample mean subtracted by M. So it is 66.34 - 20.349 = $45.991
The upper end of the interval is the sample mean added to M. So it is 66.34 + 20.349 = $86.689
The 80% confidence interval for the mean repair cost for the stereos is between $45.991 and $86.689
Answer:
400%
Step-by-step explanation:
Let the sales be "100" in 1994
Since, it decreased 80%, the sales was:
80% = 80/100 = 0.8
0.8 * 100 = 80 (decreased by 80)
So, it was
Sales in 1995: 100 - 80 = 20
Sales in 1996 was same as in 1994, so that's 100
Thus,
Sales in 1994: 100
Sales in 1995: 20
Sales in 1996: 100
We need to find percentage increase form 1995 to 1996, that is what percentage increase is from 20 to 100?
We will use the formula:
Where
New is 100
Old is 20
SO, we have:
So, it increased by 400%