Question 1
The age of the participants in a dance competition are plotted in a stem and leaf plot as shown in Figure 1.2.Q.

The IIT Madras BS Statistics for Data Science I (Stats 1) Qualifier paper sat on 7 Aug 2022, in the May 2022 term: 17 questions for 50 marks in 120 minutes. Every question is below with its answer. Take it as a timed mock test to be marked, or read it through first.
The age of the participants in a dance competition are plotted in a stem and leaf plot as shown in Figure 1.2.Q.
Correct answer
What is the value of population standard deviation of the first 2n natural numbers, i.e. 1, 2, 3, ..., 2n – 2, 2n – 1, 2n?
Correct answer
In the last 5 innings of a school cricket tournament, Manish scored 2, 4, 10, 12, and 14 runs. The population mean and the population variance of the scores of his last 7 innings are 8 and 16 respectively. What are the remaining two scores?
7 and 7
10 and 4
6 and 8
9 and 5
Correct answer
6 and 8
A free mega health checkup is conducted by a clinic at Olympia society. The systolic blood pressure (in mm Hg) of participants is listed in Table 1.1.Q. Calculate the approximate mean value of systolic blood pressure.
130.75
130.25
130
120.25
Correct answer
130.75
Consider various variables that describe the specifications of mobile phones in a store. These variables include the brands, internal storage (in GB), display size (in inches), price (in rupees), support (3G, 4G, 5G), and sim slots (single, dual). The specifications for different mobile phones are listed in a table. Based on the given information, choose the correct statement(s) from the following:
Display size (in inches), internal storage (in GB), and price (in rupees) are numerical variables.
Brands of mobile phones have the ordinal scale of measurement and internal storage (in GB) have the ratio scale of measurement.
Brands of mobile phones have the nominal scale of measurement and internal storage (in GB) have the ratio scale of measurement.
Support (3G, 4G, 5G), brands, sim slots (single, dual) are categorical variables.
Correct answers
Display size (in inches), internal storage (in GB), and price (in rupees) are numerical variables.
Brands of mobile phones have the nominal scale of measurement and internal storage (in GB) have the ratio scale of measurement.
Support (3G, 4G, 5G), brands, sim slots (single, dual) are categorical variables.
If mean, median, and mode of a numerical variable is the same, then:
All observations must have the same value as mean.
The standard deviation of the numerical variable must be zero.
All observations need not have the same value as mean.
The standard deviation of the numerical variable need not be zero.
Correct answers
All observations need not have the same value as mean.
The standard deviation of the numerical variable need not be zero.
Which of the following options represent(s) cross-sectional data? (More than one option could be correct.)
The profit of a company per year from the year 2008 to 2020.
The electricity bill of a household for each month of 2020.
The price of petrol at different cities of India on 1*^(st)* of April 2020.
The prices of stocks of a company recorded at the end of each month in the year 2020.
Correct answer
The price of petrol at different cities of India on 1*^(st)* of April 2020.
The tax paid by 100 employees of a company is given in a dataset. If the tax details of 200 more employees are added to the same dataset, then which among the following about the range will hold true? (More than one option could be correct)
The value of the range of the new dataset can never be smaller than the value of the range of the previous dataset.
The range of the new dataset can be smaller than the range of the previous dataset.
The range of the new dataset will never exceed the range of the previous dataset.
There will always be some effect on the value of the range after adding the data of 200 more employees in the dataset.
Correct answer
The value of the range of the new dataset can never be smaller than the value of the range of the previous dataset.
If the population standard deviation of the first 2n natural numbers (excluding zero) is s1, the population standard deviation of the next 2n natural numbers is s2, and the population standard deviation of the first 4n natural numbers (excluding zero) is s3, then which of the following statements is/are true?
s1 > s2
s2 = s1
s2 < s3
s1 < s3
s1 = s2 > s3
Correct answers
s2 = s1
s2 < s3
s1 < s3
If there are two variables x and y, each having n data points, where each data point is obtained by xi = i, yi = n − i, what is the correlation coefficient of x and y?
Correct answer: -1
The stem and leaf plot of the weights of 10 wrestlers is shown in Figure 1.1.Q.
What is the mean weight (in kg) of the data given in Figure 1.1.Q? (Enter the answer correct to 2 decimal accuracy.)
Correct answer: 70.6 (accepted within ±0.03)
In an organization, the manager wants to find out the relation between gender and salary earned. He calculated the absolute value of point bi-serial correlation coefficient and found it to be equal to 0.7. In the next quarter, the salary of every employee is tripled. What will be the absolute value of point bi-serial correlation coefficient after the salary is tripled? (Correct up to 1 decimal point accuracy.)
Correct answer: 0.7
The histogram in Figure 1.4.Q represents the marks distribution of 50 students of college XYZ in their Statistics quiz.
Find the approximate value of mean of the marks scored by students.
Correct answer: 68 (accepted within ±0.03)
In a college, the gender distribution of college faculty is given as stacked bar chart in Figure 1.3.Q. There are three designation for faculty: assistant professor, associate professor, and professor. The total number of assistant professors, associate professors and professors are 250, 100, and 50 respectively. Based on this information, answer the subquestions.
What is the median of faculty designation?
Associate Professor
Assistant Professor
Professor
Median is not defined for the faculty designation.
Correct answer
Assistant Professor
In a college, the gender distribution of college faculty is given as stacked bar chart in Figure 1.3.Q. There are three designation for faculty: assistant professor, associate professor, and professor. The total number of assistant professors, associate professors and professors are 250, 100, and 50 respectively. Based on this information, answer the subquestions.
Choose the correct option(s) from the following statements about the dataset given in Figure 1.3.Q.
Gender is associated with the faculty designation.
Gender is not associated with faculty designation.
Percentage of overall male faculty in the college is 65.
There is a total of 220 male faculty in the college.
Correct answers
Gender is associated with the faculty designation.
There is a total of 220 male faculty in the college.
Based on the given data, answer the subquestions.
On the basis of the information given in Table 1.2.Q, select the correct statement(s) from the following:
Receiving the damaged item is associated with the type of delivery services used.
Receiving the damaged item is not associated with the type of delivery services used.
If the manager of the retailing shop wants to reduce the number of complaints regarding the damaged items received, he should prefer delivery service of type D.
If the manager of the retailing shop wants to reduce the number of complaints regarding the damaged items received, he should prefer delivery service of type B.
Correct answers
Receiving the damaged item is associated with the type of delivery services used.
If the manager of the retailing shop wants to reduce the number of complaints regarding the damaged items received, he should prefer delivery service of type D.
Based on the given data, answer the subquestions.
Identify the correct stack bar chart representing the row relative frequencies of the type of delivery services from Table 1.2.Q.
Correct answer