Clinical Trials
7. Statistics
Exercise 8
The statements below are about Pvalues or confidence intervals. Indicate whether each statement is True or False.
The statements are:
 When the P value is less than the threshold level it implies one treatment is statistically significantly different to another:
 A narrow confidence interval implies a small sample size:
 95% confidence interval for a difference between two population means that includes 0, implies that the pvalue from a statistical test of a difference will be less than 0.05:
 95% confidence intervals are about two standard errors either side of the study mean:
 P being less than 5% indicates a clinical significance:
 A confidence interval containing 0 suggests no statistical significant difference:
 The null hypothesis should be rejected when the Pvalue is below the significance level:
 95% confidence interval will include 95% of the observations in the sample:
 A Pvalue can give insights into whether the trial was adequately powered to answer the original question:
 A Pvalue can say how effective or different a new treatment is compared with the standard treatment:
Answers:

When the P value is less than the threshold level it implies one treatment is statistically significantly different to another:
[True] 
A narrow confidence interval implies a small sample size:
[False: a narrow confidence interval implies a large sample size.] 
95% confidence interval for a difference between two population means that includes 0, implies that the pvalue from a statistical test of a difference will be less than 0.05:
[False: A confidence interval for a difference between two population means that includes 0, implies that the Pvalue from a statistical test of difference will be greater that 0.05.] 
95% confidence intervals are about two standard errors either side of the study mean:
[True] 
P being less than 5% indicates a clinical significance:
[False: If P is less than 5% it indicates a statistical significance.] 
A confidence interval containing 0 suggests no statistical significant difference:
[True] 
The null hypothesis should be rejected when the Pvalue is below the significance level:
[True] 
95% confidence interval will include 95% of the observations in the sample:
[False: A 95% confidence interval indicates that there is 95% chance that the population parameter will fall within this interval.] 
A Pvalue can give insights into whether the trial was adequately powered to answer the original question:
[It is the probability of the observed result, one or more extreme, when the null hypothesis is true] 
A Pvalue can say how effective or different a new treatment is compared with the standard treatment:
[It is the probability of the observed result, or one more extreme, when the null hypothesis is true]