Answer:
5.8
Step-by-step explanation:
Answer:
A sample of 179 is needed.
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 = 1.44.
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.
A previous study found that for an average family the variance is 1.69 gallon?
This means that 
If they are using a 85% level of confidence, how large of a sample is required to estimate the mean usage of water?
A sample of n is needed, and n is found for M = 0.14. So






Rounding up
A sample of 179 is needed.
It will be $3.68 for each rose bush because if she bought 6 of them for $22.08 then 22.08/6=3.68
The question is saying that if you buy 5 lbs, you have to pay $2.49. That means that 1 lb is $2.49/5 which (rounded to the nearest cent) is $0.50