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.
It is 70
i cant explain it right now i have work to do so sorry:)
Answer: 
Step-by-step explanation:
Remember the logarithms properties:
Then,simplifying:
Apply base 8 to boths sides and then solve for "x":
Katy is wrong because 5 divided by .25 is 20. 20 quarter pounders can be made.
Answer: 7.2 months
Step-by-step explanation:
Hi, to answer this question we have to substitute f(x) =500 in the equation given:
f(x) = 100(1.25)^x
500= 100(1.25)^x
Solving for x (number of months)
500/100 = 1.25^x
5 = 1.25^x
log 5 =log 1.25^x
log 5 =x (log 1.25)
log 5 /log 1.25 =x
x = 7.2 months
Feel free to ask for more if needed or if you did not understand something.
