Page 192 - Data Science class 10
P. 192
• Convenience: Datasets are combined to form a single, large dataset. This makes working with and evaluating the
set as a whole simple. Everything is right there in front of you, so there's no need to worry about searching through
various files or attempting to manually piece together various portions of the dataset.
2. Explain one to one join with the help of an example. [CBSE Handbook]
Ans. One to One Join: It is used to create a join between two tables in which a single row of the first table can only be linked
to one and only one row of the second table. In the same way, the row of the second table can also be linked to any row
of the first table. In this join, both tables must have primary key columns. It occurs when there is exactly one record in
Table A that corresponds to exactly one record in Table B.
Customer (Table A) Order (Table B)
Rohan Ord 101
Viraj Ord 102
Ananya Ord 103
Divya Ord 105
Suraj Ord 107
Vishal Ord 108
Anaya Ord 109
Aarush Ord 110
3. How do you calculate z-score?
Ans. The formula for calculating a z-score is:
z = (x – μ)
σ
Where,
x = Raw score
μ = Population mean
σ = Population Standard Deviation
Thus, the z-score is equal to the raw score minus the population mean, divided by the population standard deviation.
When we come across conditions where the population mean and the population standard deviation are not known,
the standard score can be determined using the sample mean, i.e., x ̄ and the sample standard deviation as estimates of
population values.
4. How do you calculate decile?
Ans. Follow the given steps to calculate decile:
Step 1 Find the number of data or variables in the sample or population. This is denoted by n.
Step 2 Now, arrange all the data or variables in the sample or population in ascending order.
Step 3 Then, based on the decile that is to be find, calculate the decile by using the formula:
(n + 1)
Di = i × 10 Data
th
Step 4 Finally, based on the decile value, find the corresponding variable from amongst the population data.
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