- Question 2 If X is a normal random variable with mean 4, and if the probability that X is more than 5.98 is 0.401, then what is the standard deviation of X? 1 point O 8.8421 O 7.8947 O 4.1052 O 9.7894 Question 3 The time taken by students to complete a STAT22 test has a normal distribution with mean 88.2 minutes and variance 149 minutes. Use the normal distribution tables to answer this question: If the students are given 1 hour and 40 minutes to complete the exam, what proportion of students will complete the exam within this given time? Mark the closest answer among the alternatives given. 1 point O 92.83% O 69.99% O 83.32% O 56.66%