Pleaseeeeeeee please help me i can’t get anymore wrong help save me please
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Answer:
B. 87
Step-by-step explanation:
The first thing is to calculate critical z factor
the alpha and the critical z score for a confidence level of 90% is calculated as follows:
two sided alpha = (100% - 98%) / 200 = 0.01
critical z factor for two sided alpha of .01 is calculated as follows:
critical z factor = z factor for (1 - .01) = z factor for (.99) which through the attached graph becomes:
critical z factor = 2.33
Now we have the following formula:
ME = z * (sd / sqrt (N) ^ (1/2))
where ME is the margin of error and is equal to 75, sd is the standard deviation which is 300 and the value of z is 2.33
N the sample size and we want to know it, replacing:
75 = 2.33 * (300 / (N) ^ (1/2))
solving for N we have:
N = (2.33 * 300/75) ^ 2
N = 86.86
Which means that the sample size was 87.
