Question 1175859
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Hi
Population:   μ = $20,000 and   σ = $2000
Sample:  n = 49 and   x̄ = $21,200
Ho:   μ =  $20,000 
Ha    μ >  $20,000
1)Level of significance is .10
2) One-tailed, critical value = invNorm(.90) =  1.2825
3) Sample > 30, population σ known: use z-test
4) {{{z =blue (x - mu)/blue(sigma/sqrt(n))}}}
      z = 1200/(2000/7) = 4.2
    z > critical value 
Reject Ho.  
Evidence shows an increase in the mean income.

Wish You the Best in your Studies.
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