# Thread: Trouble solving a simple question of statistics.

1. ## Trouble solving a simple question of statistics.

Q1.
What is the area under the standard normal curve between z = -1.28 and z = 1.28? (4dp)

What is the z-value that gives the left hand tail area equal to 0.0102? (2dp)
What is the absolute value of z such that the total area under the standard normal curve between –z and +z will be 0.7924? (2dp)

Q2.

The daily exchange rates for the two-year period 2011 to 2013 between the Japanese Yen (JPY) and the Australian Dollar (AUD) can be modelled by a Normal distribution with mean , μ = 80 Yen and a standard deviation , σ = 20 Yen.

• What is the probability that on a randomly selected day during this period, the dollar was worth less than 97 Yen? (4 dp) Answer
• What proportion of the days during this period will the dollar be worth between 64 and 97 Yen? (4 dp)Answer
• If you select a window of 175 days during this period, how many days would you expect the dollar to worth between 64 and 97 Yen?

2. ## Re: Trouble solving a simple question of statistics.

Have you tried anything?