Question 1177941
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Hi
Normal Distribution: σ = 12.9
Sample:  n = 22, x̄ = 73
90% confidence interval: two-sided(df= 21), t = 1.72
ME ={{{ z*sigma/sqrt(n)}}}
ME ={{{ 1.72*12.9/sqrt(22)}}} = 4.7
73 - 4.7< {{{mu}}} < 73 + 4.7
CI: ( 68.3, 77.7) 

Wish You the Best in your Studies.
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