Often, frequency distributions are reported using unequal class widths because the frequencies of some groups would otherwise be small or very large. Consider the following data, which represent the daytime household temperature the thermostat is set to when someone is home for a random sample of 750 households. Determine the class midpoint, if necessary, for each class and approximate the mean and standard deviation temperature.

 

Temperature (F) Frequency 61 64 31 65 67 67 68 69 198 70 195 71 72 120 73 76 89 77 80 50 Source: Based on data from the U.S. Department of Energy