Question

1. The following are outstanding credit card balances for a simple random sample of 16 college seniors:

870	419	1021	723	152	387	335	334
2618	529	769	502	485	1213	347	593

1. Use the space or the graph paper below to make a dot plot for these data.
2. What is the sample mean for this dataset?
3. What is the sample standard deviation for this dataset?
4. How many degrees of freedom are there?
5. Perform a hypothesis test for this dataset. What is your conclusion?

Answer 1

Solution-:

By using R-Software:

> Y=c(870,419,1021,723,152,387,335,334,2618,529,769,502,485,1213,347,593);Y
[1] 870 419 1021 723 152 387 335 334 2618 529 769 502 485 1213 347
[16] 593
> #For(a) Dot Plot
> dotchart(Y,main="Dot plot of outstanding credit card balances",pch=20)

> #(b)for Sample mean
> Mean=mean(Y);Mean
[1] 706.0625
> round(Mean,2)
[1] 706.06
> #(c)for sample variance and Sample S.D.
> n=length(Y);n
[1] 16
> v=var(Y);v
[1] 338245.3
> sd=sqrt(v);sd
[1] 581.5886
> round(sd,2)
[1] 581.59
> #(d)Degree of freedom
> n=16
> df=n-1;df
[1] 15

R-Code:

Y=c(870,419,1021,723,152,387,335,334,2618,529,769,502,485,1213,347,593);Y
#For(a) Dot Plot
dotchart(Y,main="Dot plot of outstanding credit card balances",pch=20)
#(b)for Sample mean
Mean=mean(Y);Mean
round(Mean,2)
#(c)for sample variance and Sample S.D.
n=length(Y);n
v=var(Y);v
sd=sqrt(v);sd
round(sd,2)
#(d)Degree of freedom
n=16
df=n-1;df