probablity problem!

stuck....

length of metal strips produced by a machine are normally distributed with mean length of 150cm and a standard deviation of 10cm.
find the probability that the length of a randomly selected strip is:

a) shorter than 165cm.

b) longer than 170cm.

c) between 145cm and 155cm.

redwood87 said:

stuck....

length of metal strips produced by a machine are normally distributed with mean length of 150cm and a standard deviation of 10cm.
find the probability that the length of a randomly selected strip is:

a) shorter than 165cm.

b) longer than 170cm.

c) between 145cm and 155cm.

Click to expand...

Since you have shown no work, you must be stuck with the concept of \(\displaystyle z\)-score. For each of the given numbers, find how far that number is from the mean, in terms of the standard deviation:
....\(\displaystyle z = \dfrac{x - \mu}{\sigma}\)

Then use a table of the normal distribution to find the probabilities associted with that \(\displaystyle z\)-value.

If you need more help, show us your work.