Revision Flashcards
Data was collected from a group of students on their year of entry to University. Possible answers were 2006, 2007, 2008 and 2009. What type of variable is this?
a. Ordinal
b. Nominal
c. Interval
d. Ratio
A
C
Which of the following represents qualitative data
a. Height of 300 students
b. Food preference of 500 patients
c. Income of healthcare professionals
d. Blood glucose levels of Obese patients
B
Which of the following is not a measure of central tendency?
a. Mean
b. Median
c. Mode
d. Variance
D
A researcher conducts a survey on a sample of 100 Uclan first year students. On the basis of data collected, the researcher concludes that the average age of all UClan first year students is 21 years. What type of statistics is this?
a. Census
b. Descriptive statistics
c. Inferential statistics
d. Experiment
C
The following sample data has been collected on the number of times a group of 7 people washed their hands in the last 24 hours: 10, 5, 2, 15, 25, 6, 4. Calculate the mean and median of these values.
a. 5.9 and 6.0
b. 9.6 and 6.0
c. 6.0 and 10.0
d. 11.0 and 8.0
B
Using the results from Q5, do the data suggest skewness in the distribution of the frequency of hand washing?
a. Yes
b. No
c. Can’t tell
A
What is the standard deviation of the data presented ?
The following sample data has been collected on the number of times a group of 7 people washed their hands in the last 24 hours: 10, 5, 2, 15, 25, 6, 4. Calculate the mean and median of these values.
7
The descriptive measure of dispersion that is based on the concept of variation around the mean is called:
a. Range
b. Interquartile range
c. Standard deviation
d. Mean
C
Suppose the 95% confidence interval for the proportion of Australians who exercise regularly is 0.29 to 0.39. Which one of the following statements is false?
a. It is reasonable to say that between 95% and 100 % of Australians exercise regularly
b. It is reasonable to say that more than 29% of Australians exercise regularly
c. The hypothesis that 30% of Australians exercise regularly is true
d. It is reasonable to say that fewer than 40% of Australians exercise regularly.
A
In hypothesis testing, type II error occurs when:
a. The null hypothesis is rejected when true
b. The null hypothesis is accepted when false
c. The null hypothesis is not rejected when true
d. The null hypothesis is not accepted when false
B
If we reject a null hypothesis, stating a drug has an effect on a disease, when in reality it has no effect at all, what type of error have we made?
a. Type I error
b. Type II error
c. Systematic error
d. Random error
A
When a null hypothesis is rejected when it should have been accepted:
a. Type I error
b. Type II error
c. Systematic error
d. Random error
A
Which of the following should be considered when selecting a statistical test?
a. Dependency of groups
b. Power
c. Significance level
d. Data volume
A
Correlation analysis is used to show:
a. Cause and effect
b. A relationship
c. Both
d. Neither
B
If the correlation between two variables is calculated to be -0.1, what conclusion can be drawn?
a. There is a very strong positive correlation between variables
b. There is a very weak positive correlation between variables
c. There is a very strong negative correlation between variables
d. There is a very weak negative correlation between variables
D
The correlation between anxiety and knowledge about covid-19 is 0.234, p value <0.001. What conclusion can be drawn from this?
a. Anxiety is a weak positive cause of increased knowledge
b. Anxiety is a strong positive cause of increased knowledge
c. Anxiety has a weak positive relationship with increased knowledge
d. Anxiety has a strong positive influence on increased knowledge
C
A research study has demonstrated that use of hand sanitizers reduced community transmission of Covid-19. Which of the following is a suitable null hypothesis?
a. Hand sanitizers reduce the risk of transmission
b. There is no difference in the risk of transmission with or without sanitizers
c. There is a lower risk of disease transmission with sanitizer use
d. There is an association between hand sanitizer use and disease transmission
B
In a study assessing the psychological impact of bullying, students who had been bullied had lower levels of self-esteem (mean 10.5 [SD 2.7] vs 12.2 [2.3], P<0.001) and higher levels of stress (mean 22.5 [SD 6.1] v 16.9 [5.8], P<0.001) than those who had not been bullied. Select all of the following statements which you believe to be true.
a) A suitable null hypothesis for this would be that students in the population who have been bullied have similar levels of self-esteem to students in the population who have not been bullied
b) There is a significant difference in the levels of self-esteem between those who had and those who had not been bullied
c) The P value for the comparison of stress was less than 0.001. This means that we cannot reject the null hypothesis at the 5% level of significance. False, we can reject the null hypothesis and conclude there is a significant difference in stress or self-esteem levels given the very small P value.
d) P < 0.001 means that there is a less than 1 in 1000 probability that the study results are due to chance.
e) We can conclude that bullying causes lower levels of self-esteem and higher levels of job-induced stress.
A
B
D
A large sample has mean of 7.1 and Standard Error of 2.3. Calculate a 95% Confidence Interval for the mean.
a. 2.5 to 9.4
b. 2.5 to 11.7
c. 2.3 to 4.6
d. 4.8 to 9.4
B
A study measured the height of randomly selected people between the ages of 18 and 30. The data was normally distributed and the mean height was 180cm with a standard deviation of 15cm. What is the 95% confidence interval around the mean if the sample size was 1,200.
a) 180 ± (1.96 x 15)
b) 180 ± (1.96 x √1,200)
c) 180 ± (1.96 x [15/√1,200])
d) 180 ± (1.96 x [1,200/√15])
C
Which statistical technique would be most appropriate for determining if students from three different faculties have equal mean IQ scores?
a) T-test
b) Chi-square
c) Regression
d) ANOVA
D
Which statistical technique would be most appropriate investigate if social class (deprived, middle class, affluent) differed between patients attending two different hospitals?
a) T-test
b) Chi-square
c) Regression
d) ANOVA
B
Blood-glucose levels in a population of 600 adult women are normally distributed with mean 90 mg/dL and standard deviation 15 mg/dL. What proportion of women in this population would have a glucose level between 60mg/dL and 120 mg/dL?
a) 15
b) 585
c) 30
d) 570
e) 60
D
Using the information provided in Q23. What proportion of women would have a glucose level above 120mg/dL?
a) 15
b) 585
c) 30
d) 570
e) 60
A
The mean blood sodium concentration of 18 cases was 115 mmol/l, with standard deviation of 12 mmol/l. Assuming that blood sodium concentration is Normally distributed, what is the 95% confidence interval within which the mean of the total population of such cases may be expected to lie?
a) 115.0 – 120.7
b) 109.3 – 120.7
c) 95.0 – 109.3
d) 109.3 – 115.7
B
In a research study, a group of 10 patients were given a new treatment for ulcer on day 1, and 6 months later they were given a standard treatment. On both occasions the researchers measured the time between start of treatment to healing of ulcer. What statistical technique would be most appropriate to investigate differences in average healing time between both treatments.
a) Paired sample T-test
b) Independent sample T-test
c) Regression
d) ANOVA
A
The following treatment times were recorded from the study described in Q27.
Standard treatment: 35, 104, 27, 53, 72, 64, 97, 121, 86, 41 days;
New treatment: 27, 52, 46, 33, 37, 82, 51, 92, 68, 62 days.
What is the mean healing time of the standard treatment?
a)65
b)55
c)60
d)70
D
What is the mean healing time of the New treatment?
a) 65
b) 55
c) 60
d) 70
B
The difference in mean healing time of both treatments is estimated to be :
15 days (95% CI - 4.30 to 34.30 days).
Which of the following represents the most appropriate conclusion?
a. None of the treatments are superior to each other
b. The new treatment has a faster healing time
c. The standard treatment has a faster healing time
d. Both treatments are ineffective
A
To investigate the relationship between certain solvents and cancer, all employees at a factory were questioned about their duration of exposure to an industrial solvent in the past 6 months. Results show that exposure to the solvent had no significant association with cancer (p<0.05) {this should have read p>0.05} . Which of the following raises the most concern about the validity of the study conclusion?
a) Attrition bias
b) Selection bias
c) Hawthorne effect
d) Recall bias
D
A triage system has been set up at a new Accident and Emergency Unit. To evaluate if the waiting times of patients at the new unit were comparable to waiting times at a nearby hospital, researchers decide to visit and monitor patient flow at both facilities for two days. What potential bias could this introduce to the study?
a) Attrition bias
b) Selection bias
c) Hawthorne effect
d) Recall bias
C
