Question

Spinocerebellar ataxia type 1 is a neurodegenerative disease marked by the gradual loss of motor skills and culminating in early death. It is caused by an expanded CAG repeat in the coding region of the Ataxin-1 gene. Fryer et al. (2011) investigated the possible beneficial effects of exercise in treating the disease. They used a mild exercise regimen in a mouse model of the disease (a mouse strain in which an expanded CAG repeat was "knocked in" to the mouse version of the same gene, and that had similar symptoms). The life spans (in days) are given below for six exercised mice and six mice not given the exercise regimen.

No exercise: 240, 261, 271, 275, 276, 281

Exercise: 261, 293, 316, 319, 324, 347

A) Is this an observational or experimental study?

B) What are the null and alternative hypotheses

C) Which statistical test would you perform for this study? Contingency analysis, one sample T-test, two sample t-test, independent (welch's) T test, or goodness of fit?

Answer 1

A)

Here researcher gave treatment "mild exercise regimen" to a group so it is a experimental study.

B)

Let shows the true average life spans for exercised mice and shows the true average life spans for non exercised mice. So hypotheses are:

C)

Since here we have two independent samples so independent (welch's) T test should be used.

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