Answer:
The confidence interval is
Step-by-step explanation:
From the question we are told that
The sample mean is
The standard deviation is
The sample size is
given that the confidence level is 85% then the level of significance is mathematically represented as
Next we obtain the critical value of from the normal distribution table the value is
Generally the margin of error is mathematically represented as
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The 85% confidence interval is mathematically represented as
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