Answer:

Step-by-step explanation:
<u><em>the mean in period</em></u> 1 :
(2.3+2.1+2.2+2.2+2.2+2.1+2.4+2.5+2.2+2.0+1.9+1.9+2.1+2.2+2.3)÷15=21.733...
<u><em>the mean in period</em></u> 2 :
(2.3+2.1+3.3+1.5+3.6+1.6+3.0+1.1+4.7+2.1+2.4+1.9+2.8+0.5+2.3)÷15=23.466...
Since 23.466 > 21.733 then “The mean in period 2 is higher than the mean in period 1”.
Answer:

Step-by-step explanation:
Given,
Red marbles = 3,
Green marbles = 10,
So, the total marbles = 3 + 10 = 13,

Since, here replacement is not allowed,
Thus, the probability of getting a green marble and a red marble
= first red and second green + first green second red




Note : The probability of getting a green marble first and a red marble second
= 


Change in temperature = 12 - (-13) = 12 + 13 = 25
Number of hours = 25/5 = 5 hours.
Required time = 4 am + 5 hours = 9.am