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From a random sample of 75 business days from January 4, 2010, through February 24, 2017,...

From a random sample of 75 business days from January 4, 2010, through February 24, 2017, Russian silver prices had a mean of $3,338.48 and σ=$205.61 was the population standard deviation of silver prices. Construct a 90% confidence interval for the true population mean µ and interpret this interval.

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Expert Solution



Solution :

Given that,

= 3338.48

= 205.61

n = 75

At 90% confidence level the z is ,

  = 1 - 90% = 1 - 0.90 = 0.10

/ 2 = 0.10 / 2 = 0.05

Z/2 = Z0.05 = 1.645

Margin of error = E = Z/2* ( /n)

= 1.645* (205.61 / 75)

= 39.06 (rounded)

At 90% confidence interval is

- E < < + E

3338.48-39.06 < < 3338.48+39.06

3299.42< < 3377.54

(3299.42,3377.54 )

orchestra answered 2 years ago
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