Two fair dice are rolled 3 times and the sum of the numbers that come up is recorded. Find the probability of these events. a. T
1 answer:
Answer:
Step-by-step explanation:
Given that two fair dice are rolled 3 times and the sum of the numbers that come up is recorded.
a) The sum is 4 on each of the three rolls.
(1,3) (2,2) (3,1) HEnce for one throw prob = 3/36 =1/12
Prob for getting same sum 4 in 3 rolls =
(since each trial is independent)
b) Prob sum =4 in exactly 2 rolls
= =
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Answer:
And the explanation of this number is:"The number of text messages for Kendra it's 2.26 deviations above the mean"
Step-by-step explanation:
1) Previous concepts
Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".
The Z-score is "a numerical measurement used in statistics of a value's relationship to the mean (average) of a group of values, measured in terms of standard deviations from the mean".
2) Calculate the z score
Let X the random variable that represent the number of text messages per month, and for this case we know the distribution for X is given by:
Where and
And the best way to solve this problem is using the normal standard distribution and the z score given by:
If we apply this formula to our probability we got this:
And the explanation of this number is:"The number of text messages for Kendra it's 2.26 deviations above the mean"
Answer:
Confidence limit = [52.8%, 75.2%]
Step-by-step explanation:
±
where the value will be taken from the z-table for 95% confidence interval
1-0.95= 0.05/2= 0.025
0.95+0.025= 0.0975
From the z-table the value of corresponding to 0.0975 is 1.96
±
±
±
% ±
%
so the confidence interval is
%
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