# Question: In Figure 4 19 we visually inspected the relative frequency histogram

In Figure 4.19, we visually inspected the relative frequency histogram for sample means based on two measurements and noted its bell shape. Another way to determine whether a set of measurements is bell-shaped (normal) is to construct a normal probability plot of the sample data. If the plotted points are nearly a straight line, we say the measurements were selected from a normal population. A normal probability plot was obtained using Minitab software. If the plot-ted points fall within the curved dotted lines, we consider the data to be a random sample from a normal distribution.
a. Do the 45 data values appear to be a random sample from a normal distribution?
b. Using the values of y in Table 4.9, compute the correlation coefficient and p-value for the normal quantile plot to assess whether the data appear to be sampled from a normal distribution.
c. Do the results in part (b) confirm your conclusion from part (a)?

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