STAT1103 Past Paper MQs

Q1. We are interested in obtaining descriptive statistics for mean animal reminder by gender as shown below. The Stata command we would use to obtain this output would be:

• tabstat Mean_Animal_reminder, statistics(mean, sd, min, max).

• by Gender, sort : summarize Mean_Animal_reminder.

• graph box Mean_Animal_reminder, over(Gender)

• tabulate Gender Mean_Animal_reminder.

Q2. Which of the following is a reason why a researcher would pick a non-experimental design over an experimental design?

• Internal validity is more important than external validity

• External validity is more important than internal validity

• Reliability is more important than validity

• Their primary aim is to control human behaviour

Q3. A scatterplot is an appropriate graphical method to study the relationship between:

• a continuous variable and a dichotomous variable.

• two continuous variables.

• two categorical variables.

• categorical variable and a discrete variable.

Q4. The assumptions for a chi-squared goodness of fit test are:

• Normality of the distribution.

• Observed values should be at least 5.

• There are no assumptions for this test.

• Expected values should be at least 5.

Q5. The degrees of freedom for a chi-squared test of independence are:

• (number of rows – 1)×(number of categories-1)

• n₁ – 2

• the numbers of categories -1

• n₁ + n₂ - 2

Q6. Happiness scores are on a numeric scale between 0 and 50. The output below is from a one sample t-test in which the null hypothesis is that the mean happiness score is equal to 30. We would conclude from the output that:

• Mean happiness is not significantly different to 30 with a small effect size.

• Mean happiness is significantly higher than 30. The effect size is small.

• Mean happiness is significantly lower than 30. The effect size is small.

• Mean happiness is significantly lower than 30. The effect size is moderate.

• Mean happiness is irrelevant.

Q7. Researchers hypothesised that vitamin C improved memory. They gave a random sample of people vitamin C and another random sample a placebo and tested their memory. The analysis I would run to compare these groups would be a(n):

• Independent samples t-test

• Chi-squared goodness of fit test

• Paired t-test

• Chi-squared test of independence

• One-sample t-test

Q8. Which of the following sentences correctly shows APA style reporting of a two sample t-test?

• The mean for males was not significantly different to females (p=0.004).

• The mean happiness score for males (M=25.0, SD=2.3) was not significantly different to females (M=24.8. SD=0.4), t(53)=0.45, p=0.652.

• The mean happiness score for males (M = 25.0, SD = 2.3) was not significantly different to females (M = 24.8, SD = 0.4), t(53) = 0.45, p = .652.

• We accept the null hypothesis that μm=μf.

Q9. The shape of the distribution of ages as shown in the histogram below is best described as:

• Skewed left

• Uniform

• Approximately uniform

• Skewed right

Q10. To obtain the histogram shown in question 9, the Stata command would be:

• graph pie, over(age)

• histogram age, density

• graph bar (count), over(age)

• histogram age, freq