Math Is Fun Forum

Troy_Hardy

Member

Registered: 2006-11-02

Posts: 1

Probabilty

6. A certain brand of chocolate bar is advertised to weigh 8.0 ounces. The distribution of the actual weights of the chocolate bars is normal with a mean of 8.1 ounces and a standard deviation of 0.1 ounce.

(a) What proportion of chocolate bars weigh more than 8.0 ounces?
(b) What is the probability a randomly selected chocolate bar has a weight between 8.2 and 8.3 ounces?
(c) The company wants to stamp a weight on the package so that only 2.5% of all chocolate bars are below that weight. What weight should they stamp on the package?

Does anyone know how to do that?

MajikWaffle

Member

Registered: 2005-12-14

Posts: 11

Re: Probabilty

AP Stats? Take your TI-83

(a) normalcdf(8.0, ∞, 8.1, .1)
(b) normalcdf(8.2,8.3,8.1,.1)
(c) invNorm(.025,8.1,.1)

or you could use the 68-95-99.7 rule.

fgarb

Member

Registered: 2006-03-03

Posts: 89

Re: Probabilty

If you don't have graphing calculator, there are many tables you can find online which give you the information you need for this, such as the one near the top of this site. If you don't understand how to use this, please ask.

http://www.statsoft.com/textbook/sttable.html