The following data is a sample of daily maximum

Question

temperatures in New York in March (from 2006-2008).
a. Calculate the mean (1 decimal place) and
standard deviation (2 decimal places) of this
data. You may use technology to answer this
question. Only the final answer is required. [3]

b. Determine a reasonable interval size and number
of intervals. Produce a properly labeled
histogram for the grouped data using technology.
Paste this graph into your solutions. [4]

c. In March, the temperatures in Seattle are
normally distributed with a mean daily
maximum temperature of 4.5ºC and a standard
deviation of 6.25ºC. What percent of days
would you predict would be between 0ºC and
10ºC? This question must be answered algebraically

I have already done part a) mean = 3.61 ; standard deviation 5.9 and part b) graph.

But I am unsure how to answer part (c)

Answer 1

c. 0 to 10 is within +- one standard deviation. Doesn't that cover 68 percent of the days?

Answer 2

yes I got that through looking at the graph but I need to show it algebraically ....so I think we have to look at the Z values
z = (x - mean)/sd
that's what I am trying to figure out