To find the mean daily high temperatures for both samples, we will sum the temperatures of each sample and then divide by the number of days (which is 10).
Sample 1: Temperatures: 78, 82, 85, 87, 90, 85, 79, 86, 91, 88
Sum of Sample 1: \[ 78 + 82 + 85 + 87 + 90 + 85 + 79 + 86 + 91 + 88 = 870 \]
Mean of Sample 1: \[ \text{Mean} = \frac{\text{Sum}}{\text{Number of Days}} = \frac{870}{10} = 87.0 \]
Sample 2: Temperatures: 81, 79, 80, 86, 89, 92, 82, 88, 84, 87
Sum of Sample 2: \[ 81 + 79 + 80 + 86 + 89 + 92 + 82 + 88 + 84 + 87 = 870 \]
Mean of Sample 2: \[ \text{Mean} = \frac{\text{Sum}}{\text{Number of Days}} = \frac{870}{10} = 87.0 \]
Now we'll calculate the difference between the mean daily high temperatures of the two samples:
Difference: \[ \text{Difference} = |87.0 - 87.0| = 0.0 \]
Thus, the mean daily high temperature of Sample 1 is 87.0°, the mean daily high temperature of Sample 2 is 87.0°, and the mean daily high temperatures of the two samples differ by 0.0 (rounded to the nearest tenth).