We can review a histogram of our sample to see that

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Unformatted text preview: ten, in statistical analyses, we are required to verify that our data plausibly come from a normal distribution. We can review a histogram of our sample to see that the data have a roughly bell-shaped form. A more thorough way to check normality is to make a special plot called a normal probability plot (sometimes called a normal quantile plot). 1. From the STAT PLOTS menu, turn on one plot. 2. For Type, choose the very last option, as in the screen to the right. Press [. 3. To display the plot, remember to press B 9. 3. Descriptive Statistics: Summarizing Quantitative Variables Scatterplots, Correlation, Finding the Regression Statistics, and Residual Plots Press K and select CALC. Select option 1:1–Var Stats. Type in your list name by pressing F and one of the number keys from 1 through 6. Press [. 3. To see all the results, scroll down to the bottom of the screen. Note: Pay close attention when the calculator screen displays an arrow pointing up or down—this means there is more information available that you can find by scrolling. Inferences for Proportions These instructions assume that you have entered your explanatory (otherwise called predictor or independent) variable in L1 and your response (or dependent) variable in L2. To make a scatterplot: 1. From the STAT PLOTS menu, turn on one plot. 2. For Type, choose the very first option as in the screen to the right. Be sure to press [ after your selection. 3. Xlist contains the list name of your explanatory variable, L1. To type in L1, press F and 1. 4. Ylist contains the list name of your response variable, L2. To select that name, press F and 2. 5. To display the plot, press B 9. Pressing C will allow you to identify individual points in the plot. To make a confidence interval for a population proportion: 1. Press K and scroll to the TESTS menu. Scroll down until you find the option 1–PropZInt and select it. 2. Enter the number of successes (x) and sample size (n) for your sample. (Be sure to enter the number, not proportion, of successes.) 3. Determine your confidence level and select Calculate. Press [. The screen displays the confidence interval inside a set of parentheses and reports the sample proportion and sample size. Note: Your instructor may want you to use a plus-4 interval, also known as the adjusted Wald confidence interval, or a small sample interval. To use these formulas, add 2 to the number of successes you observed and add 4 to the sample size, then follow the above procedures. 1. 2. ISBN-13: 978-0-321-57077-2 ISBN-10: 0-321-57077-4 90000 1 9 780321 570772 2 3 TI_card_570774_reprint.qxp 2/12/09 3:43 PM Page 2 TI–83/84® Inferences for Proportions (continued) Confidence Intervals and Hypothesis Tests for a Mean Inference for Two Sample (Independent) Means (continued) To do a hypothesis tests for a proportion: 1. Write down your null and alternative hypotheses. 2. Press K and scroll to the TESTS menu. 3. Scroll down to 1–PropZTest and press [. 4. Look at your null hypothesis and type in th...
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This document was uploaded on 01/28/2014.

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