Combined Mean, Standard Deviation and Variance

[sue]

Thank you very much for uploading this as i requested from the previous standard deviation, you video, your voice is very audible and clear to the point. you really need more views and likes on this. i have checked almost all your video, starting from mean, median mode standard deviation, and combined and must you say you are excellent. keep uploading more. THUMBS UP. ONINAB RESOURCES.

[alawiyyasulaimanilu]

Thank u sir very helpful, my Allah reward u for helping us

[davidbrennan]

Thank you very much for the video, very helpful.

Do the variables have to be independent for them to be combined in this way?

If so, is there another way to combine dependent variables?

[SharanGaming]

Do I have to follow the same method, when the means are same for two samples? Please reply.

[s.ethhhh]

Hi! This was really informative. I have a question though. If the question gives us a sample instead of population, do we simply just change N into n-1 ? For example, in this question, will it become (40-1)(5^2+6^2) and the denominator will become (40+60-1)?

[FaizShakirNure]

Baay'ee galatomi I love you thanks for giving best tutorial

[tebitheirrychick]

Is combined standard deviation the same as covariance square???

[peterchikoya]

(a) A service station has recorded the following frequency distribution for the number of gallons of gasoline sold per car in a sample of 680 cars.

Gasoline (gallons) 0–4, 4 – 8, 8 – 12, 12 – 16, 16 – 20, 20 – 24
frequency 74 , 192, 280 , 105 23 6

(i) Compute the mean (2 marks)
(ii) Compute the variance (5 marks)
(iii) Compute the coefficient of variation. (2 marks)

help me with this question

[asogvideos]

Love the way you present, awesome and helpful

[ringkhangdaimary]

Thank you so much sir for well teach to us 🍓💝

[umangkashyap]

What if variance is given and standard deviation not given

[brightonyasa]

Please can you do quadratic equetion graph please Sir.

[FathimaSameeha-xb]

Variance answer is not correct sir pls explain