Final answer:
To calculate the mean high temperature for the given week, add all the daily high temperatures and then divide by the number of days. The sum of the temperatures is 539, and when divided by 7 days, the mean is 77°.
Step-by-step explanation:
The question is asking for the mean high temperature for a week in July. To find the mean temperature, you add up all the high temperatures for each day and then divide by the number of days.
Using the data provided:
Sunday 74°, Monday 75°, Tuesday 80°, Wednesday 76°, Thursday 75°, Friday 81°, and Saturday 78°, the sum is 74 + 75 + 80 + 76 + 75 + 81 + 78 = 539.
Now, divide this sum by the number of days in the week, which is 7:
539 ÷ 7 = 77°
Therefore, the mean high temperature for the week is 77°, which corresponds to answer choice D.