Sarah is ceebrating her 13 birthday. She has invited her 11 friends over. If her mom baked 2 birthday cakes. How many pieces of
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Answer:
Step 1: The estimate the proportion of tenth graders reading at or below the eighth grade level is 0.2.
Step 2: The 99% confidence interval for the population proportion of tenth graders reading at or below the eighth grade level is (0.181, 0.219).
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 z-score that has a p-value of .
Suppose a sample of 2845 tenth graders is drawn. Of the students sampled, 2276 read above the eighth grade level.
So 2845 - 2276 = 569 read below, and the estimate of the proportion of tenth graders reading at or below the eighth grade level is:
, and the answer to step 1 is 0.2.
The sample size is
99% confidence level
So , z is the value of Z that has a p-value of
, so
.
The lower limit of this interval is:
The upper limit of this interval is:
The 99% confidence interval for the population proportion of tenth graders reading at or below the eighth grade level is (0.181, 0.219).