I collected some data about how many buyers of my book liked it (on a scale of 1 = it’s utter rubbish) to 10 (It is the only book I will ever read). I ended up with a sample of 15,467 people. When I looked at the distribution, I found a mean of 4.78 (SD = .65). What is the z-score for my data? *NOTE: Population mean = 6.82 (SD = .47).

I used the z-score formula using the sample population, but I got a big number (not your normal z-score). Just not sure what to do.... Thanks for any help!

Question

I collected some data about how many buyers of my book liked it (on a scale of 1 = it’s utter rubbish) to 10 (It is the only book I will ever read). I ended up with a sample of 15,467 people. When I looked at the distribution, I found a mean of 4.78 (SD = .65). What is the z-score for my data?  *NOTE: Population mean = 6.82 (SD = .47). 

I used the z-score formula using the sample population, but I got a big number (not your normal z-score). Just not sure what to do.... Thanks for any help!