Question: Sometimes a researcher must decide whether a variable is normally distributed. There are several ways to do this. One simple but very subjective method uses special graph paper, which is called normal probability paper.

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Boundaries Frequency

89.5-104.5 24

104.5-119.5 62

119.5-134.5 72

134.5-149.5 26

149.5-164.5 12

164.5-179.5 4

If the points fall approximately in a straight line, it can be concluded that the distribution is normal. Do you feel that this distribution is approximately normal? Explain

To find the approximation of the mean or median, draw a horizontal line from 50% point on the y axis over to the curve and then a vertical line down to the x axis, compare this approximation of the mean with the computed mean