A, B, and C are not choice answers, they're small questions.
2 answers:
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Answer:
x=12
Step-by-step explanation:
For the given situation , a quantity x is added to gives 15.
We can set up equation as
Multiply each term by 4 on both sides to get rid the denominator.
It gives,
4 x+x=60
Now, combine like terms
5 x=60
Divide both sides by 5
x=12.
Answer:
The 80% confidence interval for the mean number of toys purchased each year is between 7.5 and 7.7 toys.
Step-by-step explanation:
We have that to find our level, that is the subtraction of 1 by the confidence interval divided by 2. So:
Now, we have to find z in the Ztable as such z has a pvalue of .
That is z with a pvalue of , so Z = 1.28.
Now, find the margin of error M as such
In which is the standard deviation of the population and n is the size of the sample.
The lower end of the interval is the sample mean subtracted by M. So it is 7.6 - 0.1 = 7.5
The upper end of the interval is the sample mean added to M. So it is 7.6 + 0.1 = 7.7
The 80% confidence interval for the mean number of toys purchased each year is between 7.5 and 7.7 toys.