Statistics

Question 1

In evaluating differences between mean values of clinical chemistry variables from an animal toxicity study on Day 1 vs. Day 14, statistical analyses are used, and a p-value of <0.05 for several comparisons were derived. What does a p-value of <0.05 mean?
A. the differences between the variable means are statistically and biologically significant
B. the significant differences between means were caused by the treatment
C. the probability that the the observed response had no effect is less than 1 in 20
D. the probability that the observed response had no effect is less than 1 in 20

Answer 1

C. the probability that the the observed response had no effect is less than 1 in 20

Explanation and Reference:
The significance level is the chance of obtaining a false positive result due to sampling error (known as a Type I error). It is usually set at 5%, although lower levels are sometimes specified. In other words, it is the probability that the null hypothesis is true. Statistical significant tells the investigator nothing about biological significance or whether the differences are true or not. Hayes 6th, p. 377