__20 Mathematics and Statistics Interview Questions and Answers __

Mathematics and statistics form part of our daily lives and routines and therefore knowledge in these areas is very important. It is this knowledge that will even help you to sail through that mathematics and statistics interview. **1. What is Algebra?**

**Answer**: Algebra is one of the fields of maths, which uses symbols and letters to represent numbers, points, and objects, as well as the relationship between them. It is used to know the unknown variables.

**2. What is Exterior Angle in a polygon? ****Answer**:
In polygons, the angle between any side of the shape and a line
extended from the next side is referred to as Exterior Angles. The sum
of exterior angles of the polygon is 360°.

**3. What is exploratory data analysis? ****Answer**:
Exploratory data analysis is the process of performing investigations
on data to understand the data better. In this, initial investigations
are done to determine patterns, spot abnormalities, test hypotheses, and
also check if the assumptions are right.

**4. What are the types of selection bias in statistics? ****Answer**:

- Observer selection
- Attrition
- Protopathic bias
- Time intervals
- Sampling bias

**5. What is the meaning of an inlier? ****Answer**:
An inlier is a data point that lies at the same level as the rest of
the dataset. Finding an inlier in the dataset is difficult when compared
to an outlier as it requires external data to do so. Inliers, similar
to outliers reduce model accuracy. Hence, even they are removed when
they’re found in the data. This is done mainly to maintain model
accuracy at all times.

**6. What is the meaning of standard deviation? ****Answer**:
Standard deviation represents the magnitude of how far the data points
are from the mean. A low value of standard deviation is an indication of
the data being close to the mean, and a high value indicates that the
data is spread to extreme ends, far away from the mean.

**7. What is the difference between Descriptive and Inferential Statistics? ****Answer**:

- Descriptive Statistics: Descriptive statistics is used to summarize a sample set of data like the standard deviation or the mean.
- Inferential statistics: Inferential statistics is used to draw conclusions from the test data that are subjected to random variations.

**8. What is the meaning of covariance? ****Answer**:
Covariance is the measure of indication when two items vary together in
a cycle. The systematic relation is determined between a pair of random
variables to see if the change in one will affect the other variable in
the pair or not.

**9. Where is inferential statistics used? ****Answer**:
Inferential statistics is used for several purposes, such as research,
in which we wish to draw conclusions about a population using some
sample data. This is performed in a variety of fields, ranging from
government operations to quality control and quality assurance teams in
multinational corporations.

**10. How can you calculate the p-value using MS Excel? ****Answer**: the following steps are performed to calculate the p-value easily:

- Find the Data tab above
- Click on Data Analysis
- Select Descriptive Statistics
- Select the corresponding column
- Input the confidence level

**11. What is the difference between an error of type I and an error of type II? ****Answer**:

- When the null hypothesis is rejected even though it is correct, a type 1 error occurs. False positives are also known as type 1 errors.
- When the null hypothesis is not rejected despite being incorrect, a type 2 error occurs. This is also known as a false negative.

**12. What is sampling? ****Answer**:
Selecting an unbiased or random subset of individual observations in a
population is regarded as part of the statistical practice of sampling.
In order to obtain some understanding of the population, sampling is
used.

**13. What is the Central Limit Theorem? ****Answer**:
Central Limit Theorem is the cornerstone of statistics. It states that
the distribution of a sample from a population comprising a large sample
size will have its mean normally distributed. In other words, it will
not have any effect on the original population distribution. Central
Limit Theorem is widely used in the calculation of confidence intervals
and hypothesis testing. Here is an example – We want to calculate the
average height of people in the world, and we take some samples from the
general population, which serves as the data set. Since it is hard or
impossible to obtain data regarding the height of every person in the
world, we will simply calculate the mean of our sample.

**14. What is the Law of Large Numbers in statistics? ****Answer**:
According to the law of large numbers, an increase in the number of
trials in an experiment will result in a positive and proportional
increase in the results coming closer to the expected value. As an
example, let us check the probability of rolling a six-sided dice three
times. The expected value obtained is far from the average value. And if
we roll a dice a large number of times, we will obtain the average
result closer to the expected value (which is 3.5 in this case).

**15. What are the types of biases that you can encounter while sampling? ****Answer**:

- Undercoverage bias
- Observer Bias
- Survivorship bias
- Self-Selection/Voluntary Response Bias
- Recall Bias
- Exclusion Bias

**16. What is a statistical interaction? ****Answer**:
A statistical interaction refers to the phenomenon which occurs when
the influence of an input variable impacts the output variable. A
real-life example includes the interaction of adding sugar to the
stirring of tea. Neither of the two variables has an impact on
sweetness, but it is the combination of these two variables that do.

**17. What is the relationship between mean and median in normal distribution? ****Answer**: In a normal distribution, the mean and the median are equal.

**18. Why do we need sample statistics? ****Answer**: Sampling in statistics is done when population parameters are not known, especially when the population size is too large.

**19. What is the difference between Line, Point, Plane, and Solid? ****Answer**:

- Point has no dimensions
- Line is one-dimensional
- Plane is two dimensional
- Solid is three dimensional

**20. What is Cubic Meter? ****Answer**: Cubic Meter is the standard unit used to measure the volume of an object length by length. The unit is written in m3.

What
you need to do now is to believe in yourself because a mathematics and
statistics interview is just an interview like any other. It is easier
for you to pass if you want to. Just make sure that you perfectly
remember the questions with answers you have read above and you will be
good to go.

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