Browsing as Guest. Progress, bookmarks and attempts are disabled.
Log in to track your work.
Nov 2014 p61 q2
2964
The number of phone calls, X, received per day by Sarah has the following probability distribution.
x
0
1
2
3
4
≥5
P(X = x)
0.24
0.35
2k
k
0.05
0
Find the value of k.
Find the mode of X.
Find the probability that the number of phone calls received by Sarah on any particular day is more than the mean number of phone calls received per day.
Solution
(i) The sum of all probabilities must equal 1:
\(0.24 + 0.35 + 2k + k + 0.05 = 1\)
\(0.64 + 3k = 1\)
\(3k = 0.36\)
\(k = 0.12\)
(ii) The mode is the value of \(x\) with the highest probability. Here, \(P(X = 1) = 0.35\) is the highest, so the mode is 1.