Often, frequency distributions are reported using unequal class widths because the frequencies of some groups would otherwise

Question:

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