Answer:
Hence the 90% confidence interval estimate of the population mean is
Step-by-step explanation:
Given that,
Point estimate = sample mean = = 88.34
sample standard deviation = s = 19.22
sample size = n = 14
Degrees of freedom = df = n - 1 = 13
Critical value = df = 1.771
Margin of error
Margin of error = E = 9.10
The 90% confidence interval estimate of the population mean is,
Given:
Principal = $3000
Rate of interest = 4.7% = 0.047 compounded quarterly.
Time = 12 yeas
To find:
The value of John’s investment after 12 years.
Solution:
The formula for amount is
where, P is principal, r is rate of interest, n is number of times interest compounded in an year, t is number of years.
Substitute P=3000, r=0.047, n=4 and t=12 in the above formula.
Therefore, the required equation is .
We can further solve this.
Therefore, the value of John’s investment after 12 years is $5255.76.