Microsoft Office Tutorials and References
In Depth Information
Research hypothesis H 1 : l 4
STEP 2: Select the appropriate statistical test
In this chapter we are studying the confidence interval about the mean, and so
we will select that test.
STEP 3: Calculate the formula for the statistical test
You will recall (see Sect. 3.1.5 ) that the formula for the confidence interval
about the mean is:
X ts : e :
ð 3 : 2 Þ
We discussed the procedure for computing this formula for the confidence
interval about the mean using Excel earlier in this chapter, and the steps involved
in using that formula are:
1. Use Excel’s = count function to find the sample size.
2. Use Excel’s = average function to find the sample mean, X .
3. Use Excel’s = STDEV function to find the standard deviation, STDEV.
4. Find the standard error of the mean (s.e.) by dividing the standard deviation
(STDEV) by the square root of the sample size, n.
5. Use Excel’s TINV function to find the lower limit of the confidence interval.
6. Use Excel’s TINV function to find the upper limit of the confidence interval.
STEP 4: Draw a picture of the confidence interval about the mean, including the
mean, the lower limit of the interval, the upper limit of the interval, and the
reference value given in the null hypothesis, H 0 (We will explain Step 4 later in the
chapter).
STEP 5: Decide on a decision rule
(a) If the reference value is inside the confidence interval, accept the null
hypothesis, H 0
(b) If the reference value is outside the confidence interval, reject the null
hypothesis, H 0 , and accept the research hypothesis, H 1
3.2.3.6
STEP 6: State the result of your statistical test
There are two possible results when you use the confidence interval about the
mean, and only one of them can be accepted as ‘‘true.’’ So your result would be
one of the following:
Either: Since the reference value is inside the confidence interval,
we accept the null hypothesis, H 0
Or: Since the reference value is outside the confidence interval,
we reject the null hypothesis, H 0 , and accept the research
hypothesis, H 1
Search JabSto ::




Custom Search