how many area codes are possible if the first digit can’t be zero, no digit can be repeated, and the third digit must be 9 or 0?
1 answer:
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Answer:
The sample size is
Step-by-step explanation:
From the question we are told that
The sample proportion is
The margin of error is
Given that the confidence level is 95% the level of significance is mathematically represented as
Next we obtain the critical value of from the normal distribution table , the values is
The reason we are obtaining critical value of instead of
is because
represents the area under the normal curve where the confidence level interval (
) did not cover which include both the left and right tail while
is just the area of one tail which what we required to calculate the margin of error
Generally the margin of error is mathematically represented as
substituting values
=>