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WorksheetsIVY-ATLAS-STAT-August 20
Total questions: 15
Worksheet time: 24mins
Name
Class
Date
1.
The lowest significance level that results in rejecting the null hypothesis is known as
a)
α value
b)
p value
c)
test statistic
d)
confidence interval
2.
The median household income for people aged 25-34 is ₹492,780.
What type of statistics is being used?
a)
Descriptive
b)
Inferential
c)
Individual
d)
Sample
3.
The value appearing at the centre of a sorted version of a list, or the mean of the two central values.
a)
Median
b)
Range
c)
Mean
d)
Mode
4.
Summarizes data using a single number. The single number is found by finding the sum of the data divided by the number of pieces of data.
a)
Median
b)
Range
c)
Mean
d)
Mode
5.
The mean of a distribution is 23, the median is 24, and the mode is 25.5. It is most likely that this distribution is:
a)
Positively Skewed
b)
Symmetrical
c)
Asymptotic
d)
Negatively Skewed
6.
According to the empirical rule, approximately what percent of the data should lie within μ ± 2σ?
a)
75%
b)
68%
c)
99.7%
d)
90%
e)
95%
7.
Which of the following is not a measure of central tendency?
a)
Percentile
b)
Quartile
c)
Standard Deviation
d)
Mode
8.
The distance between the greatest number and the least number in a set of data.
a)
Mean
b)
Median
c)
Range
d)
Mode
9.
Which of the following statements about the P value to be true?
a)
The P value is the probability that the null hypothesis is true.
b)
The P value is the probability that the alternative hypothesis is true.
c)
The P value is the probability of obtaining the observed or more extreme results if the alternative hypothesis is true.
d)
The P value is the probability of obtaining the observed results or results which are more extreme if the null hypothesis is true.
e)
The P value is always less than 0.05.
10.
Subjects from families with genetic disorders were asked whether they had encountered problems when applying for life insurance. A sample from the general population was also asked the same question. About a third of respondents in the study group (723/2167) reported problems compared with only 5% of the general population. This difference was significant at the 0.01% level. Select all of the following statements which you believe to be true.
a)
A suitable null hypothesis would be that subjects from families with genetic disorders in the population are more likely to experience problems when applying for life insurance than those from the general population.
b)
We can reject the null hypothesis at the 5% level of significance.
c)
A suitable alternative hypothesis would be that subjects from families with genetic disorders in the population are more likely to experience problems when applying for life insurance than those from the general population.
d)
The result is significant at the 0.01% level. This means that we are 0.01% certain that the null hypothesis is true.
e)
The differences between the two groups of families are likely to have occurred by chance.
11.
In a study of workplace bullying in a community NHS trust, staff were asked about whether workplace bullying had affected their working environment. Staff who had been bullied had lower levels of job satisfaction (mean 10.5 [SD 2.7] vs 12.2 [2.3], P<0.001) and higher levels of job-induced 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 can be true.
a)
A suitable null hypothesis for this would be that staff in the population who have been bullied at work have similar levels of job satisfaction to staff in the population who have not been bullied at work.
b)
There is a significant difference in the levels of job satisfaction between those who had and those who had not been bullied
c)
The P value for the comparison of job-induced stress was less than 0.001. This means that we cannot reject the null hypothesis at the 5% level of significance.
d)
P < 0.001 means that there is a less than 1 in 1000 chance that we would have obtained these results, or more extreme results, if the alternative hypothesis was true.
e)
We can conclude that work place bullying causes lower levels of job satisfaction and higher levels of job-induced stress.
12.
Which of the following statements about confidence intervals to be true?
a)
A confidence interval gives an estimated range of values which is likely to include an unknown population parameter.
b)
A 95% confidence interval gives the range of values which is likely to include 95 out of a 100 sample data values.
c)
A 95% confidence interval is wider than a 99% confidence interval.
d)
A confidence interval can be calculated using an estimate of the parameter plus a multiple of the standard deviation. If you want to increase the width of the confidence interval you should increase the sample size.
13.
If the mean value for the weight of 25 men was calculated to be 90 kg with a standard deviation of 10 kg, what would the 95% confidence interval for the mean weight be approximately?
a)
84 to 96
b)
86 to 94
c)
80 to 100
d)
70 to 110
14.
Which of the following are measures of central tendency?
a)
Mean
b)
Standard deviation
c)
Variance
d)
Median
e)
Mode
15.
Chosse which of the following statements are true?
a)
A positively skewed variable has a long right hand tail when drawn as a histogram.
b)
The mean should be reported as the measure of central tendency for data with a left skewed distribution.
c)
The median should be reported as the measure of central tendency for data with a right skewed distribution.
d)
Either the mean or the median should be reported for a continuous variable.
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