Answer:
609
Step-by-step explanation:
Standard deviation = 
= $30
Margin of error = E = $2
Confidence level = 90%
Since the distribution is said to be normal, we will use z scores to solve this problem.
The z score for 90% confidence level = z = 1.645
Sample size= n = ?
The formula to calculate the margin of error is:
Using the values in above equation, we get:
This means, the minimum number of observations required is 609
Answer:
Step-by-step explanation:
6+3=9/50
9/50 x 100=18 percent
Answer:
43.35 years
Step-by-step explanation:
From the above question, we are to find Time t for compound interest
The formula is given as :
t = ln(A/P) / n[ln(1 + r/n)]
A = $2500
P = Principal = $200
R = 6%
n = Compounding frequency = 1
First, convert R as a percent to r as a decimal
r = R/100
r = 6/100
r = 0.06 per year,
Then, solve the equation for t
t = ln(A/P) / n[ln(1 + r/n)]
t = ln(2,500.00/200.00) / ( 1 × [ln(1 + 0.06/1)] )
t = ln(2,500.00/200.00) / ( 1 × [ln(1 + 0.06)] )
t = 43.346 years
Approximately = 43.35 years
