Question

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. µ [?- E. ?=E what is the probability that µ is contained in the interval?

Answer 1

SOLUTION:

From given data,

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. µ [?- E. ?=E what is the probability that µ is contained in the interval

mean = = 3338.48

standard deviation = σ= 205.61

sample size = n = 75

Let us take ,

At 90% confidence level the z is ,

= 1 - 90% = 1 - 0.90 = 0.10

/ 2 = 0.10 / 2 = 0.05

Z_/2 = Z_0.05 = 1.645

Margin of error = E = Z_/2 * (σ / )

= 1.645* (205.61 / )

= 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 )

the probability that µ is contained in the interval is  (3299.42 , 3377.54 )

dear ma'm / sir you didn't mention  confidence level in your question ...but i was submitted this answer as per my knowledge i was taken as 90% of  confidence level ....if you want this answer with different confidence level...you can comment me i will re post it...