Ask Ghassem - Recent questions in general

How do I compare the count of a value in each year while having a different sanple size each year.

Wed, 08 Jun 2022 10:32:33 +0000

How do I accurately compare between the number of something a survey measure from my employees each year with a varying umber of survey engagement and employee size?

If I was measuring the satisfaction of my employees over the years by collecting a survey from my them each year by asking them wether they are satisfied or not, and then comparing yes’s over the years but the number of employees who answer is not the same each year and the number of employees increases every year. How do I correctly compare this throughout each year?

In other words, how do I remove the effect of the survey engagement rate when calculating the results?

Using aggregate data to generate observation-level data statistically sound?

Tue, 11 Jun 2019 22:04:01 +0000

Context: In the realm of Paid Search Marketing. Current reporting does not provide event level data only aggregate totals with different segments. Want to compare distributions/test statistical significance of A/B test results. Did not want to assume that data followed normal distribution or know STDEV for data so came with this approach.

My Question: I am going to use the average "CPA" or "CTR" for a date range, and generate an observation for each conversion based off the average for a time range. Is this statistically sound way if I want to generate raw data? Would I have wonky distributions because of the multiple averages? Just want a gutcheck if I'm completely off base.

My Aggregate data looks like below:

Day	Cost	Acquisition	CPA or CTR
1	40	2	$20
2	75	3	$25

Observation data I generate looks like below:

Day	Acquisition
1	$20
1	$20
2	$25
2	$25
2	$25

I really appreciate your help with this question! An important project to me at work.

What is the rule that determines percentages with the mean +- 1,2 or 3 standard deviations?

Sat, 17 Nov 2018 19:03:35 +0000

What will be probability for the data items within mean +- 1, +-2, +-3 standard deviation?

Wed, 14 Nov 2018 15:10:15 +0000

How much percentage of data items are consumed within mean +-1 , +-2, +-3 standard deviation?

Wed, 14 Nov 2018 15:04:52 +0000

What is a test statistic in hypothesis testing and how does it relate to the p-value?

Tue, 13 Nov 2018 00:51:11 +0000

What is sampling error?

Tue, 13 Nov 2018 00:47:51 +0000

In the first week of November 2003.... What is the expected number of homicides per week in the GTA?

Fri, 02 Nov 2018 19:34:40 +0000

This is from question one from lecture 4B's exercises: "In the first week of November 2003, five unrelated homicides were reported in the GTA. The GTA usually has about 78 homicides per year. What is the expected number of homicides per week in the GTA?"

In statistics, whats the difference between contingency and frequency tables?

Tue, 30 Oct 2018 11:19:48 +0000

How do you tell a permutation problem from a combination problem?

Mon, 15 Oct 2018 15:34:13 +0000

Given the questions:

1. How many different groups of 4 students can be made from a class of 40?

and

2. How many different lists of 4 students can be made from a class of 40?

How do you determine which requires a permutation and which requires a combination?

What is a discrete random variable?

Sat, 13 Oct 2018 01:23:24 +0000

What is the difference between permutation and combination?

Sat, 13 Oct 2018 01:19:28 +0000

What is the difference between Qualitative and Quantitative data?

Sat, 13 Oct 2018 01:15:59 +0000

If x is the number that comes up when you roll a 20 sided die. What is the expected value of x?

Fri, 12 Oct 2018 22:43:05 +0000

If x is the number that comes up when you roll a 20 sided die. What is the expected value of x?

What is the probability of getting a King of Hearts?

Fri, 12 Oct 2018 22:31:45 +0000

What is the probability of picking a King of Hearts in a standard 52 card deck?

Define measures of center (Median and Mode) ?

Fri, 12 Oct 2018 22:28:59 +0000

Define the 2 measures of centers.

What is "Random Sampling"?

Fri, 12 Oct 2018 22:26:06 +0000

Define random sampling

What is binomial experiment and when do we use it?

Fri, 12 Oct 2018 22:25:59 +0000

When should we use permutation and combination?

Fri, 12 Oct 2018 22:16:45 +0000

Calculate IQR(Inter Quartile Range) of {18, 24, 19, 16, 21}?

Fri, 12 Oct 2018 22:07:58 +0000

What do population, parameter, census and sample mean in statistics?

Fri, 12 Oct 2018 21:50:34 +0000

Question for Discrete random variable

Fri, 12 Oct 2018 21:00:40 +0000

An investor has a 0.60 probability of making a 20000 dollar profit and a 0.40 probability of suffering a 25000 dollar loss. What is the expected value?

Sample question of permutation and combination.

Fri, 12 Oct 2018 20:47:03 +0000

You can bring along 2 friends! you have 5 friends who want to come along. How many different groups of friends could you take with you?

{1.75, 1.63, 1.55, 1.92, 1.81, 1.79, 1.81}. Determine the mean, the median, and the 20th percentile?

Fri, 12 Oct 2018 19:42:32 +0000

What is difference between discrete numerical variable and continuous numerical variable?

Fri, 12 Oct 2018 19:25:11 +0000

What is the difference between Combination and Permutation?

Thu, 11 Oct 2018 17:25:28 +0000

As an example:
Calculate the possible permutations for a rubik's cube?

Why is it not, calculate the possible combinations for a rubik's cube?

Six devices (A,B,C,D,E, F) are each assigned one of three IP addresses...how many different assignments are possible?

Mon, 08 Oct 2018 21:46:42 +0000

Six devices (A,B,C,D,E, F) are each assigned one of three IP addresses (IP#1, IP#2, IP#3). If three
devices are assigned IP#1, two devices are assigned IP#2, and one device IP#3, how many different
assignments are possible?

This is question 4 from lecture 3A.

How many different ways are there to deal four 13 card hands to four players from a standard deck of 52 cards?

Mon, 08 Oct 2018 18:58:32 +0000

This question is from the third Combination example from lecture notes 3A. Researching this question I found this answer

https://www.quora.com/In-how-many-ways-can-52-cards-be-distributed-to-four-players-with-13-cards-each

What I don't understand is why you multiple the number of ways for each hand as opposed to adding. I know for player 1 it's C(52,13), player 2 C(39,13), player 3 C(26,13), then player 4 is 1 or C(13,13). I thought adding these together would get the total number of ways to deal the cards. Is this answer from the link correct and why?

What is the difference between the mean and the median? Calculate both for the following number set {18, 24, 19. 16. 21}

Fri, 05 Oct 2018 20:20:21 +0000

What is the difference between qualitative and quantitive data?

Tue, 02 Oct 2018 19:06:43 +0000

A standard deck of 52 cards is shuffled and a single card is drawn. What is the probability that this card is a Joker

Mon, 01 Oct 2018 19:51:38 +0000

This is question 1d in the 2B exercises. The answer says the probability is 0 but I count 4 jokers in a 52 card deck, which means the probability is 1/13. Think I misunderstand the question. Why is it 0?

What is the difference between a bar plot and a histogram?

Mon, 01 Oct 2018 13:09:35 +0000