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.
Answer: 9
Step-by-step explanation:
The factors of 27 are: 1, 3, 9, 27
The factors of 36 are: 1, 2, 3, 4, 6, 9, 12, 18, 36
The factors of 54 are: 1, 2, 3, 6, 9, 18, 27, 54
Then the greatest common factor is 9.
Hope this helped ! :)
Answer:
it has one solution
Step-by-step explanation:
1.y=x-3
2. 3y-3x sub x-3 in place of y therefore
it can also be written as 3x-3x-9=9
if you add 9 to both sides 3x-3x-9+9=-9+9
0+0=0