Unformatted text preview: your conﬁdence level and select Calculate. Press [. The screen displays the conﬁdence
interval inside a set of parentheses and reports the two sample proportions and sample sizes.
To do a hypothesis test on the difference between two proportions:
1. Write down your null and alternative hypotheses.
2. Press K and scroll to the TESTS menu.
3. Scroll down until you ﬁnd the option 2 – PropZTest and select it.
4. Enter the number of successes (x1) and sample size (n1) for the ﬁrst sample.
(Again, the number not proportion of successes.)
5. Enter the number of successes (x2) and sample size (n2) for the second sample.
6. Look at your alternative hypothesis. In the row beginning with the symbol p1, use the arrow keys to move the cursor left or right
to select the correct form of your alternative hypothesis. Press [ to select it.
7. Move the cursor over Calculate and press [. The output screen repeats the form of the alternative hypothesis selected. The
test statistic, z, and the pvalue, p, are given. The two sample proportions are calculated and reported, while the phat without a
subscript is the pooled sample proportion. The sample sizes are also displayed, but you need to scroll down to see these.
As before, you can also select the option Draw in the 2 –PropZTest. 4 The line beginning with m allows you to select the form of the alternative hypothesis—use the arrow keys to move the cursor left or
right to select the correct form of your alternative hypothesis. Press [ to select it.
8. Select Calculate and press [. The screen repeats the form of the alternative hypothesis selected. The test statistic, t, and the
pvalue, p, are reported, along with the sample’s summary statistics.
As before, you can also select the option Draw to see the test results. Inference for Two Sample (Independent) Means
Note: These procedures will ask if you want to use the pooled standard deviation procedures—these are
rarely used, so use them only if your instructor tells you to.
To make a confidence interval for the difference between two population means:
1. Press K and scroll to the TESTS menu.
2. Scroll down until you ﬁnd the option 2–SampTInt and select it.
3. If you have the data, select the Data option, and enter the list names with the data. See the top screen
to the right.
4. If you have only the summary statistics, choose the Stats option and enter the summary statistics
(sample mean and standard deviation, and sample size) for each of your samples. See the second
screen to the right.
5. Determine your conﬁdence level.
6. If you are using the pooled procedures, select Yes; otherwise, select No. You may have to scroll down to
see this line.
7. Scroll down and select Calculate. Press [. Displayed is the interval for the difference m1  m2. Other
details of the calculation are also displayed: the degrees of freedom and all the summary statistics. You need
to scroll down to see them all.
To conduct a hypothesis test:
1. Write down your null and alternative hypotheses.
2. Press K and scroll to the TESTS menu.
3. Scroll down until you ﬁnd the option 2–SampTTest and select it.
4. If you have the data, select the...
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 Spring '14
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