Statistics homework

Short answer

Let's think about a medical treatment. One group is administered a drug, the other a placebo. Each knows that are getting something. Individuals vary. Some improve spontaneously, some because of positive thinking, some deteriorate, some improve because of the drug, some improve because they think they are taking the drug, some have differences in biochemistry that results in variable susceptibility to the drugs effect, etc, etc, - all individual difference error factors. But we want to know if the drug is effective, so we chose the .05 alpha level and go about partialling out the differences between the groups. That's 95% probability that we can reject the null. F-ratio tells us about how much difference exist between groups once all the error factors are partialled out. ANOVA: A simple but powerful concept.

Complete assignment.

Data 2019

A study was conducted to test the impact of a reading intervention on kindergarten children’s acquisition of beginning reading skills. In order to gauge progress, a number of measures were used, including measures of the acquisition of sound equivalents of letters, letter names, concept of number, sight words, reading comprehension, etc. Letter naming has been found to be an effective proxy for overall development.

In this study, you are asked to analyze the results of the upper and lower case (52) letter naming assessment.

60 subjects were randomly assigned to two groups, an experimental group and a “waiting group” control. All subjects were assessed three times, prior to treatment (Oct. 15), after ten weeks, and after 20 weeks. The experimental group was enrolled in the intensive reading program for the first ten weeks, and then received no treatment for the next ten weeks. The “waiting group”, received no treatment for the first ten weeks, and then was enrolled in the intensive reading group for the next ten weeks. Three data points were thus gained.

The appropriate statistic to use in this example is a repeated measure (dependent sample) analysis of variance. However, neither the student version of SPSS, nor Excel, has a sufficiently sophisticated statistic to do a complete analysis. So for your project, find the means and standard deviations for the pre, mid, and post measures for each of the groups (a total of 6). If you had a repeated measure capability, you would then complete a post hoc analysis, probably using Tukey’s statistic. Since you don’t, I am asking you to draw what logical conclusions you can by simply looking at the means and noting differences, and then, accounting for history, development and other external and internal threats to validity, draw tentative conclusions.

Group 1

Group 2