Eli takes a typing test and types all 300 words in 1/10hour.
1 answer:
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to solve for j first you need to cross multiply;
j × 35 = 42 × 55
35j = 2,310
j = 2,310 ÷ 35 (did the inverse operation)
j = 66
Hope that helps :D
Answer:
We need at least 243 stores.
Step-by-step explanation:
In a sample with a number n of people surveyed with a probability of a success of , and a confidence level of
, we have the following confidence interval of proportions.
In which
z is the zscore that has a pvalue of .
The margin of error of the interval is:
For this problem, we have that:
95% confidence level
So , z is the value of Z that has a pvalue of
, so
.
Determine the number of stores that must be sampled in order to estimate the true proportion to within 0.04 with 95% confidence using the large-sample method.
We need at least n stores.
n is found when M = 0.04. So
Rounding up
We need at least 243 stores.