Biologists studying the healing of skin wounds measured the rare at which new cells closed a razor cut made in the skin of an anesthetized newt. Here are data from 18 newts, measured in micrometers per hours: 29,27,34,40,22,28,14,35,26,35,12,30,23,18,11,22,23,33. Make a stemplot of the healing rates (split the stems). Is is difficult to assess Normality from 18 observations, but look for outliers or extreme skewness. What do you find?
b)Scientists usually assume that animal subjects are SRSs from their species or genetic type. Treat these newts as an SRS and suppose you know that the standard deviation of healing rates for this species of newt is 8 micrometers per hour. Give a 90% confidence interval for the man healing rate for the species.
I think what Sherasi is asking is what is your question? What you have given us looks like a homework problem. As a general policy, people here do not simply do other peoples' homework for them. If someone has the necessary knowledge, I'm sure they would help you see your way to the answer if you could explain what your difficulty is.
(Edit: and of course I post this and Sherasi's side of the conversation disappears)
Typically a scatter plot involves an x and y input for each point to see how the two items relate.
A histogram may be more appropriate.. Find your highest and lowest data point and determine the range of your data. divide this range into six or eight 'buckets' of smaller ranges.. you have 40 and 11 or about 30 um/hr range...6 buckets ..about 5 units each
<10, 10-15,16-20,21-25,25-30,>30.. Ideal data will give you a Gausian bell curve. Many software packages can do the hard work for you. but Even the Eyeball sketch will show your data looks pretty normal. I don't see any outliers..
Your std Deviation was close to the published data @8.25 vs 8 um/hr..
SRS (standard representative sample?)..
Your mean of 25.7 um/hr.. your question was to give a range of numbers that the mean could be if you were not 'perfect' they want you to be 90% sure of your answer..
Range= Mean +/- [Std dev/(sqrt (N-1)]* t t= a table look up for Student's t
