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    The heights of sunflowers may be assumed to be normally distributed with a mean of 185cm and a standard deviation of 10cm.

    b.) Determine the probability that the mean height of a random sample of 4 sunflowers is more than 190cm

    I've never been taught how to do questions like this? I think it has something to do with the variance but I'm not 100% sure what that means either. I can't find any online guide for questions like this so if someone could link me to one or explain it below I'd really appreciate it.
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    (Original post by Retsek)
    The heights of sunflowers may be assumed to be normally distributed with a mean of 185cm and a standard deviation of 10cm.

    b.) Determine the probability that the mean height of a random sample of 4 sunflowers is more than 190cm

    I've never been taught how to do questions like this? I think it has something to do with the variance but I'm not 100% sure what that means either. I can't find any online guide for questions like this so if someone could link me to one or explain it below I'd really appreciate it.
    For a random sample of size n taken from a random variable

    X\sim N(\mu, \sigma^2)

    the sample mean \bar{X} is normally distributed with

    \bar{X}\sim N(\mu, \frac{ \sigma^2 }{n})

    Does this help? Where are you up to in stats? You'll learn this at some point.
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    (Original post by Notnek)
    For a random sample of size n taken from a random variable

    X\sim N(\mu, \sigma^2)

    the sample mean \bar{X} is normally distributed with

    \bar{X}\sim N(\mu, \frac{ \sigma^2 }{n})

    Does this help? Where are you up to in stats? You'll learn this at some point.
    Thanks! I can't read it yet though because the app doesn't support Latex :'( We finish the entirety A-level stats in a couple weeks all we've got left is using the large data sets and normal distribution hypothesis testing, I'll ask my teacher about it and find out if it's something we just haven't been taught yet.
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    (Original post by Retsek)
    Thanks! I can't read it yet though because the app doesn't support Latex :'( We finish the entirety A-level stats in a couple weeks all we've got left is using the large data sets and normal distribution hypothesis testing, I'll ask my teacher about it and find out if it's something we just haven't been taught yet.
    It should be taught as part of normal distribution hypothesis testing (in the Edexcel textbook it's in the same chapter) so I don't think you need to worry.

    You learnt it all in a couple of weeks! Why so fast? Also, it's best to use the mobile site instead of the app when using the maths forum
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    (Original post by Notnek)
    It should be taught as part of normal distribution hypothesis testing (in the Edexcel textbook it's in the same chapter) so I don't think you need to worry.

    You learnt it all in a couple of weeks! Why so fast? Also, it's best to use the mobile site instead of the app when using the maths forum
    We didn't do it all in a couple of weeks sorry bad wording, we've been doing it since September and will finish the a-level course in a few weeks, glad I haven't missed anything on the course, will definitely check out the mobile site as well
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    (Original post by Retsek)
    We didn't do it all in a couple of weeks sorry bad wording, we've been doing it since September and will finish the a-level course in a few weeks
    Your wording was fine - I just misread your post
 
 
 
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Updated: February 23, 2018
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