A-Level Maths: N2-09 Normal Distribution: A Worded Problem 2

[@AndyVLSmith]

Your videos on normal distribution make it such an easier to understand topic, thank you.

[@TLMaths]

Glad to help!

[@shussain1429]

I’ve just come across your channel and I have to say your a absolutely brilliant. I hate stats and you’ve been an absolute lifesaver!

[@peterjames5071]

Thanks, Jack! Exceedingly helpful as always!

[@jordanw9387]

Hi Jack - will we always be told that it's a normal distribution like we are here? Or expected to decide if it's binomial / normal / uniform?

[@TLMaths]

It should be clear in the question which you are using. Normal will use mean and variance, binomial will use n and p.

[@jordanw9387]

@@TLMaths Thankyou x

[@adiljaved1330]

Hello, I have a question. Isn‘t it possible to just take a big sample, note down how long they last and then divide it by the number of samples to get the mean?

[@TLMaths]

I don't have the population to hand to take samples from though

[@dontbenosey.1]

Question, when would normal PD ever be used and what's its function? Thanks

[@TLMaths]

Essentially it calculates the height of the normal distribution curve at that point

[@abinayaganesharaj5687]

How do you know how many decimal places to give the mean and sd to? Thanks for this video btw it’s rly helpful!

[@TLMaths]

It can depend on the question, but usually 3sf is appropriate.

[@ariannejane3455]

im a tiny bit confused with the mean and standard deviation answers. i got 42.2 as the standard deviation and 106 as the mean, i dont know what ive done wrong

[@kingslayer2212]

Since you can't have 10.5 days, wouldn't it be more suitable to round down to 10 days? Because according to the distribution it won't reach 11 days?

[@TLMaths]

Why can't you have 10.5 days? And I wouldn't want to round any mean and standard deviation, especially if I go on to use those values), to anything worse than 3sf.

[@ProletarianNuklearWarrior]

Isn't 1% meaning 0.001% ? Wouldn't 0.01 mean lowest 10% ? I used 0.001 and That gave me a value of 61.46

[@TLMaths]

1% is 0.01 as a decimal. 10% is 0.1 as a decimal.