Re: Difficult time with this problem, , ,
- From: "web2.0" <rwest.eagle@xxxxxxxxx>
- Date: Mon, 25 Feb 2008 08:19:40 -0800 (PST)
On Feb 25, 8:49 am, David Winsemius <doe_s...@xxxxxxxxxxx> wrote:
"web2.0" <rwest.ea...@xxxxxxxxx> wrote in news:66d6d5a3-3f53-467b-99ae-
92f5b7bb6...@xxxxxxxxxxxxxxxxxxxxxxxxxxxx:
Bank of America's Consumer Spending survey collected data on annual
credit card charges in seven different categories of expenditures:
transportation, groceries, dining out, house-hold expenses, home
furnishings, apparel, and entertainment. Using data from a sample
of 42 credit card accounts, assume that each account was used to
identify the annual credit card charges for groceries (population
1), and the annual credit card charges for dining out (population
2). Using the difference data, the sample mean was Dbar = $850, and
the sample standard deviation was Sd = $1123.
Formulate the null and alt hyps, to test for no difference between
the pop mean credit charges for groceries and the population mean
credit card charges for dining out.
Use a .05 level of significance. Can you conclude that the
population means differ?
what is the p value?
which category , groceries or dining out, has a higher population
mean annual credit card charge? What is the point estimate of the
difference between the population means? What is the 95% confidence
interval estimate of the difference between the population means?
---------------
The way i'm starting this problem is: T = DBar - U_d divided by S_d /
sqrt(N)
meaning 850-0 / 1123/sqrt(42)
i come out to 850 / (1123/6.4807)
I come out w/ a value of 4.905 as test statistic, but this is wrong.
How do you know that "this is wrong"? And wrong by how much?
That number, of course, is not the answer to any of the questions that
were posed.
--
David Winsemius- Hide quoted text -
- Show quoted text -
500, 1200 is the 95% CI range?
what seems to throw me off is the D_0 portion being zero, leaving
850-0 in the top part.
ANy pointers on where to start.
this is a matched pair sampling problem yes?
.
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