1. What is linear regression?

Modeling the relationship between a scalar variable y and one or more variables denoted X. In linear regression, models of the unknown parameters are estimated from the data using linear functions.
polyfit( x,y2,1) %return 2.1667 -1.3333, i.e 2.1667x-1.3333

2. What is null hypothesis?

The null hypothesis (denote by H0 ) is a statement about the value of
a population parameter (such as mean), and it must contain the condition of equality and must be written with the symbol =, ≤, or ≤.

3. Explain central limit theorem?

As the sample size increases, the sampling distribution of sample
means approaches a normal distribution
If all possible random samples of size n are selected from a population with mean μ and standard deviation σ, the mean of the sample means is denoted by μ x̄ , so
μ x̄ = μ
the standard deviation of the sample means is:
σ x̄ = σ⁄√ n

4. Explain hash table?

A hash table is a data structure used to implement an associative array, a structure that can map keys to values. A hash table uses a hash function to compute an index into an array of buckets or slots, from which the correct value can be found.

5. Do you know what is binary search?

For binary search, the array should be arranged in ascending or descending order. In each step, the algorithm compares the search key value with the key value of the middle element of the array. If the keys match, then a matching element has been found and its index, or position, is returned. Otherwise, if the search key is less than the middle element's key, then the algorithm repeats its action on the sub-array to the left of the middle element or, if the search key is greater, on the sub-array to the right.

6. What is binomial probability formula?

P(x)= p x q n-x n!/[(n-x)!x!]
where n = number of trials
x = number of successes among n trials
p = probability of success in any one trial
q = 1 -p

7. Give example of Central Limit Theorem?

Given that the population of men has normally distributed weights, with a mean of 173 lb and a standard deviation of 30 lb, find the probability that
a. if 1 man is randomly selected, his weight is greater than 180 lb.
b. if 36 different men are randomly selected, their mean weight is greater that 180 lb.

Solution: a) z = (x - μ)/ σ = (180-173)/30 = 0.23
For normal distribution P(Z>0.23) = 0.4090
b) σ x̄ = σ/√n = 20/√ 36 = 5
z= (180-173)/5 = 1.40
P(Z>1.4) = 0.0808

8. What is significance level?

The probability of rejecting the null hypothesis when it is called
the significance level α , and very common choices are
α = 0.05 and α = 0.01

9. What is alternative hypothesis?

The Alternative hypothesis (denoted by H1 ) is the statement that must be true if the null hypothesis is false.

10. What is one sample t-test?

T-test is any statistical hypothesis test in which the test statistic follows a Student's t distribution if the null hypothesis is supported.
[h,p,ci] = ttest(y2,0)% return 1 0.0018 ci =2.6280 7.0863