Friday, September 19

• Generating Content through Interpreting Study Data

IPHY 3700 Writing Process Map

Process Activity: Generating Content through Interpreting Research Data

Interpret the statistical significance of study data.

Interpret the practical significance of study data.

Record the ideas from your interpretation in goal-based notes.

Results from Golay et al.’s Study

Golay et al.

Guidelines for Interpreting Statistical and Practical Significance

A P value is the probability of obtaining your study's result (or a more extreme result) under the assumption that the null hypothesis is true. In other words, a P value is the probability of obtaining your study's result (or a more extreme result) by chance.

P values are strongly influenced by sample size and the variability of individual data points. As sample size increases and variability decreases, P values decrease; so, in these conditions the probability of obtaining statistically significant results increases.

P values never indicate the practical significance of study data; so, small P values never indicate great "importance" of study data.

Study data may be statistically significant but practically insignificant.

Study data that are not statistically significant (e.g., P > .05) can sometimes be practically significant.

To interpret the practical significance of study data you have to know your science and your math!

Handout: A Brief Explanation of P Values

Interpret Golay et al.’s Results

Golay et al.

Conversions of Golay et al.’s Results

15% CHO 45% CHO

  Before After Before After

Glucose (mg/dL) 95.4 79.2 97.2 90.0

Insulin (pmol/L) 106.8 57.6 96.0 88.2

Total Cholesterol (mg/dL)

222.3 175.5 237.9 206.7

HDL Cholesterol (mg/dL)

42.9 35.1 42.9 39.0

Triacylglycerol (mg/dL)

151.3 124.6 195.8 160.2

To convert mmol/L of glucose to mg/dL, multiply by 18To convert mmol/L of cholesterol to mg/dL, multiply by 39To convert mmol/L of triacylglycerol to mg/dL, multiply by 89

Interpret Johnston et al.’s Results

The thermic effect was significantly greater for the high-protein meal versus the high-carbohydrate meal at breakfast and dinner.

Interpret Latner & Schwartz’s (1999) Results