Answer: 1692
Step-by-step explanation:
Formula to find the sample size :
Given : Confidence level :
⇒ significance level =
z-value for 90% confidence interval (using z-table)=
Prior estimate of the population proportion (p) of customers who keep up with regular vehicle maintenance is unknown.
Let we take p= 0.5
Margin of error : E= 2%=0.02
Now, the required sample size will be :
Simplify , we get
Hence, the required sample size = 1692
Let x- intercept represents time
Let y-intercept represents population
Let 1990 represent initial year
Points are (0,14.2)(10,12.4)
slope m=
=
General linear equation
y= mx+b --------------(i)
here m is slope and b is intercept
plug the 1st point in equation
14.2= -0.018(0) + b
b=14.2
y= 0.018x + 14.2
replace y with p(t) and x with t
p(t) = -0.018t + 14.2
Answer:
(B) (0.396, 1.712)
Step-by-step explanation:
From the information given;
Confidence Interval = 0.95
Significance Level
The confidence interval for regression coefficient beta (whereby in this case it is the coefficient of the diameter) is expressed by:
=
From the regression coefficient, the estimated value of beta^ = 1.054