This webpage is designed to help out with using Statcrunch. I highly recommend using Statcrunch in this course.
I will be adding to this site as the semester goes along. If you ever feel that is lacking in an area, please let me know and I'll do my best to improve it.
Chapter 1
Statcrunch is not useful in Chapter 1
Chapter 2
Section 2.3
Scatter plot: Click the little box to the right of the data set and select "Open in Statcrunch". Now that Statcrunch is open, click "Graph" and then "Scatter Plot". Select the two variables for the X variable and Y variable. Click "Compute".
Dotplot: Click the little box to the right of the data set and select "Open in Statcrunch". Now that Statcrunch is open, click "Graph" and then "Dotplot". Select the variable. Click "Compute".
Stem and Leaf Plot: Click the little box to the right of the data set and select "Open in Statcrunch". Now that Statcrunch is open, click "Graph" and then "Stem and Leaf". Select the variable. Click "Compute".
Chapter 3
Just about everything in this chapter can be found using the same procedure in Statcrunch.
mean, median(Q2), standard deviation, variance, minimum, Q1, Q3, maximum:Click the little box to the right of the data set and select "Open in Statcrunch". Now that Statcrunch is open, click "Stat", "Summary Stats", then "Columns". Select the variable. Click "Compute".
Boxplot:Click the little box to the right of the data set and select "Open in Statcrunch". Now that Statcrunch is open, click "Graph" and then "Boxplot". Select the variable. Check the box next to "Draw boxes horizontally". Click "Compute".
Chapter 4
Statcrunch is not useful for this chapter.
Chapter 5
Section 5.2
Binomial distribution: For finding the probability of the number of successes in a certain number of trials. Open statcrunch, click "Stat", "Calculators", and "Binomial". Enter in the number of trials (n) and the probability of success (p). On the last line enter in the number of successes desired (x) and the appropriate symbol (>=, <=, or =). Click "compute".
Chapter 6 The probabilities from this chapter can be found using statcrunch but I recommend learning using table A-2 first--using the table will give you a better understanding of the concept which will be important for this chapter and future chapters.
Section 6.1
Standard normal probabilities: Open statcrunch, click "Stat", "Calculators", and "Normal". Enter in the mean (0 if you're using the standard normal distribution) and the standard deviation (1 if you're using the standard normal distribution). Enter in the Z value in question and choose the appropriate symbol (<=, >=,=). Click compute.
Finding scores from known areas/probabilities: Example: Find the score corresponding to P90. Open statcrunch, click "Stat", "Calculators", and "Normal". Enter in the mean (0 if you're using the standard normal distribution) and the standard deviation (1 if you're using the standard normal distribution). The last line should read... P(X<=______) = 0.90. Click compute.
Section 6.2
Normal Probabilities: This is done exactly the same as section 6.2 except the mean and standard deviation has changed.
Section 6.4
Central Limit Thm. Finding the probability for a mean of a group: This is done in the same way. The only difference is that the standard deviation changes when you are dealing with a mean of a group. You enter the mean as you done in the previous sections but the standard deviation changes when dealing with a mean of a group. The new standard deviation is the standard deviation divided by the square root of n. For example, if the standard deviation is 50 and the sample size is 100 you need to manually calculate and enter the new standard deviation as 50/sqrt(100) = 50/10 = 5.
Chapter 7
Section 7.1
Finding the Za/2 value: Open Statcrunch, click "Stat", "Calculators", and "Normal". Enter in the mean (enter 0) and standard deviation (enter 1). The last line should read...
P(X>=______) ="half the value of alpha".
Click "compute".
Confidence intervals for Proportions: Open Statcrunch, click "Stat", "Proportion Stats", "One Sample", "with summary". Enter in the given information (number of successes and number of observations) and select "Confidence interval for p". Enter in the appropriate confidence level and click "Compute"
Finding sample size requirement for proportions: Open Statcrunch, click "Stat", "Proportion Stats", "One Sample", "width/sample size". Enter in the confidence level, Target proportion (enter .5 if unknown), width (note the width is twice the margin of error). Click calculate.
Section 7.2
Finding the Ta/2 value: Open Statcrunch, click "Stat", "Calculators", and "T". Enter in the degrees of freedom. The last line should read...
P(X>=______) ="half the value of alpha".
Click "compute".
Confidence intervals for Means: Open Statcrunch, click "Stat", "T Stats", "One Sample", "with summary". Enter in the given information (mean, standard deviation, and sample size) and select "Confidence interval for mu". Enter in the appropriate confidence level and click "Compute"
Note: There is a problem or two in this section that gives you the raw data rather than the summarized form. For these problems we do the following: Click the little box to the right of the data set and select "open in statcrunch". Click "Stat", "T Stats", "One Sample", "with data". Select the data set and select "Confidence interval for mu". Enter in the appropriate confidence level and click "Compute".
Finding sample size requirement for mean: Open Statcrunch, click "Stat", "Z Stats", "One Sample", "width/sample size". Enter in the confidence level, standard deviation, and width (note the width is twice the margin of error). Click calculate.
Chapter 8
Section 8.1
Finding the critical Z value :Open Statcrunch. Click "Stat", "Calculators", and "Normal". Once the calculator comes up, enter in the mean (enter 0) and standard deviation (enter 1).
For a right tailed test....P(X>=____________) = “given alpha value”
For a left tailed test.... P(X<=____________) = “given alpha value”
For a two tailed test with positive test statistic.... P(X>=____________) = “HALF the given alpha value”
Click "compute". Note: If it’s a two tailed test you’ll need the negative and positive of the resulting Z value.
Finding a P-value from the Normal distribution:Open Statcrunch. Click "Stat", "Calculators", and "Normal" Once the Calculator comes up, enter in the mean (enter in 0) and the standard deviation (enter in 1) and the last line should read...
For a right tailed test....P(X>="given test statistic") = ______
For a left tailed test....P(X<="given test statistic") = ______
For a two tailed test with positive test statistic....P(X>="given test statistic") = ______
For a two tailed test with negative test statistic....P(X<="given test statistic") = ______
Click "compute". Note: If it's a two tailed test the P-value will have to be doubled.
Section 8.2
Hypothesis Test for Proportions: Open Statcrunch, click "Stat", "Proportion Stats", "One Sample", "with summary". Enter in the given information (number of successes and number of observations). Enter in the appropriate null hypothesis and alternative. Click "Compute". This will give you the test stat and p-value.
Section 8.3
Finding the critical T value :Open Statcrunch. Click "Stat", "Calculators", and "T". Once the calculator comes up, enter in the number of degrees of freedom and the last line should read..
For a right tailed test....P(X>=____________) = “given alpha value”
For a left tailed test.... P(X<=____________) = “given alpha value”
For a two tailed test with positive test statistic.... P(X>=____________) = “HALF the given alpha value”
Click "compute". Note: If it’s a two tailed test you’ll need the negative and positive of the resulting T value.
Finding a P-value from the T distribution:Open Statcrunch. Click "Stat", "Calculators", and "T". Once the Calculator comes up, enter in the degrees of freedom (n-1) and the last line should read...
For a right tailed test....P(X>="given test statistic") = ______
For a left tailed test....P(X<="given test statistic") = ______
For a two tailed test with positive test statistic....P(X>="given test statistic") = ______
For a two tailed test with negative test statistic....P(X<="given test statistic") = ______
Click "compute". Note: If it's a two tailed test the P-value will have to be doubled.
Hypothesis Test for Means: Open Statcrunch, click "Stat", "T Stats", "One Sample", "with summary". Enter in the given information (mean, standard deviation, and sample size). Enter in the appropriate null hypothesis and alternative. Click "Compute". This will give you the test stat and p-value.
Note: There is a problem or two in this section that gives you the raw data rather than the summarized form. For these problems we do the following: Click the little box to the right of the data set and select "open in statcrunch". Click "Stat", "T Stats", "One Sample", "with data". Select the data set and enter in the appropriate null hypothesis and alternative. Click "Compute". This will give you the test stat and p-value.
Chapter 9
Section 9.1
Hypothesis Test for Two Proportions: Open Statcrunch, click "Stat", "Proportion Stats", "Two Sample", "with summary". Enter in the given information (number of successes and number of observations for both groups). Enter in the appropriate null hypothesis (0) and alternative. Click "Compute". This will give you the test stat and p-value.
Confidence Intervals for Two Proportions: Open Statcrunch, click "Stat", "Proportion Stats", "Two Sample", "with summary". Enter in the given information (number of successes and number of observations for both groups) and select "Confidence interval for p1 - p2". Enter in the appropriate confidence level and click "Compute". Note: If the significance level is .05 and it's a one tailed test (left or right) then the confidence interval will be 90%, not 95% because there has to be the same value in each tail.
Section 9.2
Hypothesis Test for Two Means: Open Statcrunch, click "Stat", "T Stats", "Two Sample", "with summary". Enter in the given information (mean, standard deviation, and sample size for both groups). Enter in the appropriate null hypothesis (0) and alternative. Uncheck the box marked pooled variances. Click "Compute". This will give you the test stat and p-value.
Confidence intervals for Two Means: Open Statcrunch, click "Stat", "T Stats", "Two Sample", "with summary". Enter in the given information (mean, standard deviation, and sample size for both groups) and select "Confidence interval for u1 -u2". Uncheck the box marked pooled variances. Enter in the appropriate confidence level and click "Compute". Note: If the significance level is .05 and it's a one tailed test (left or right) then the confidence interval will be 90%, not 95% because there has to be the same value in each tail.
Section 9.3
Hypothesis test for Paired Means: Click the little box to the right of the data set and choose "Open in Statcrunch". Once Statcrunch is open click "Stat", "T Stats", "Paired". Select the data in sample 1 and sample 2. Enter in the appropriate null hypothesis (0) and alternative. Click "Compute". This will give you the test stat and p-value.
Chapter 10
Section 10.1
Correlation Coefficient: Click the little box next to the data set and choose "Open in Statcrunch". Click "Stat", "Regression", and "Simple Linear". Select the two variables (X and Y)and click "Compute". This will give you a huge amount of information but there is only a couple things that you'll need. Toward the top you'll see R (correlation Coefficient) and if asked for the test stat and/or p-value you can find that on the "slope" row of information.
Section 10.2
Regression Equation: Click the little box next to the data set and choose "Open in Statcrunch". Click "Stat", "Regression", and "Simple Linear". Select the two variables (X and Y)and click "Compute". The regression equation will be one of the first things given.
Chapter 11
Section 11.1
Finding P-Values when Test Statistic is given: Open Statcrunch, click "stat", "calculators", and "chi-square". Enter in the degrees of freedom and the last line should read:
P(X>="given test stat")=_______ . Click calculate.
Goodness of Fit Test: Click the little box next to the data set and choose "Open in Statcrunch" (you might have to type the data in manual on some). Click "Stat", "Goodness of Fit", and "Chi-Square". Select the data set under "Observed". Check the box next to "All cells in equal proportion". Click "Compute".
Section 11.2
Contingency Tables: Click the little box next to the data set and choose "Open in Statcrunch". Click "Stat", "Tables", "Contingency", "with summary". Under "Select columns" choose the the columns with data values in them. Under "row labels" select the column with the names. Click "Compute".