Page 135 - Data Science class 10
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Standard Questions (Section B)
A. Short answer type questions:
1. What is data science?
Ans. Data science is a science of exploring available data and utilising it in your day-to-day transactions. It is a field that
works with and examines large amounts of data to give meaningful information that can be used for making decisions
and solving problems.
2. What is row-based subsetting?
Ans. In this method of subsetting, we take some rows from the top or bottom of the table.
3. What is a frequency table?
Ans. A frequency table is a table that lists items and shows the number of times the items occur.
4. What do you mean by two-way frequency table?
Ans. A two-way table is a statistical table that determines the observed number or frequency for two variables, the rows
indicate one category and the columns indicate the other category.
5. Define central tendency.
Ans. Central tendency means the value derived from the random variables in the set of data that reflects the midpoint of the
data distribution.
6. Name the three types of mean.
Ans. There are three types of mean which are as follows:
• Arithmetic mean
• Geometric mean
• Harmonic mean
B. Long answer type questions:
1. How do you calculate the number of subsets?
Ans. The number of subsets can be determined from the number of elements in the set. Therefore, if there are 3 elements as
3
in this case, there are: 2 = 8 subsets. Remember that the empty (or null) set and the set itself are subsets. The number
n
of subsets is always 2 where n is the number of elements in the set.
2. Find the mean, median, mode, and range for the following list of values:
8, 9, 10, 10, 10, 11, 11, 11, 12, 13
Ans. The mean is the usual average, so you shall add up and then divide:
(8 + 9 + 10 + 10 + 10 + 11 + 11 + 11 + 12 + 13) = 105 ÷ 10 = 10.5
The median is the middle value. In a list of ten values, average the fifth and sixth numbers is used to find the median.
The fifth and sixth numbers in the order are the last 10 and the first 11, so:
(10 + 11) ÷ 2 = 21 ÷ 2 = 10.5
The mode is the number repeated most often. This list has two values that are repeated three times; namely, 10 and 11,
each repeated three times.
The largest value is 13 and the smallest is 8, so the range is 13 – 8 = 5.
3. How do you create a frequency table?
Ans. To create a frequency table, follow the steps given below:
Step 1 Make three columns. The first column contains the data values in ascending order (from lesser to large values).
Step 2 The second column contains the number of times the data value occurs using tally marks. Count for every row
in the table. Use tally marks for counting.
Step 3 Count the number of tally marks for each data value and write it in the third column.
4. What is Mean Absolute Deviation?
Ans. The Mean Absolute Deviation (MAD) of a dataset is the average distance between each data value and the mean. It
helps us get a sense of how "spread out" the values in a dataset are. MAD is the average of how far away all values in
a dataset are from the mean.
Use of Statistics in Data Science 133

