Statistics: linear regression on the HP-10B
The tutor shows how to get a best-fit line with the HP-10B. Imagine the following data: x y 3 10.1 4 14.7 9 32.5 12 47.1 To get a best-fit line for it of form y=mx+b, here are the steps: …
Category: statistics
Statistics: Spreadsheets: the frequency() function
The tutor shares a nice function that seems to work the same in Excel or LibreOffice Calc. The frequency() function tells, from an array of values and another of categories, the frequency in each category. A potential use is to …
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Statistics: Spreadsheets: tdist() function
The tutor covers the tdist() function, which seems to work the same on Excel and LibreOffice Calc. The tdist() function is in the statistics category of functions. Its entry scheme is =tdist(t-value, degrees_of_freedom, number_of_tails) Perhaps surprisingly, the t-value itself must …
Statistics: comparison between normal and t-distribution, df=24
The tutor shows an example of z vs t. From yesterday’s post, we have the following parameters: x: 14.4 sample standard deviation: 3.3 sample size: 25 We estimated the percent of the population between 10.2 and 12.9. Using the t-statistic …
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Statistics: using t-statistics on the TI-83 Plus
The tutor gives an example of how to use the TI-83 Plus to get results from the t-distribution. Let’s imagine the following situation: Sample size: 25 Sample mean: 14.4 Sample standard deviation: 3.3 Estimate the percent of the population between …
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Statistics: 1-β : type II error and the power of a test
The tutor continues about hypothesis testing and type II errors. In yesterday’s post I began about hypothesis testing, type I, and type II errors. Specifically, a type II error would be continuing to believe the mean loaf mass is 454g, …
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Statistics: hypothesis testing: type I and type II errors
The tutor explores the questions, from statistics, “What is a type I error? What is a type II error?”, with a couple of examples. In statistics, hypothesis testing is done when you think you know a value but want confirmation. …
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Statistics: the matched pairs t-test
The tutor shows an example of the matched pairs t-test. In my post from Dec 11 I began about the matched pairs t-test. It’s used to determine if two samples come from the same population. In my previous post I …
Perl: random numbers, but less random
The tutor prepares for a statistics experiment. The first step is to generate two lists: one random, one less so. To generate fifteen random numbers with Perl one can use the following code: for ($i=0;$i
Statistics: the matched-pairs t-test: justification of the use of the t-distribution
The tutor comments about why the t-distribution can be used for the matched-pairs test. The matched-pairs t-test is used to determine if two samples come from the same distribution. The data is collected in pairs, one to each sample, and …
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