Louise Johnson
Junior Member
- Joined
- Jan 21, 2007
- Messages
- 103
Question#1
The standard deviation of the following population, correct to two decimal places is:
\(\displaystyle \L\\\left\{ {25,31,33,50,72,81,85,90,93} \right\}\)
my answer: \(\displaystyle \L\\\sigma = 25.93\)
Question #2
The weight of each piece of bubble gum produced by a machine is normally distributed with a mean of 12g and a standard deviation of 0.5g. Determine the percentage of pieces of bubble gum which will be expected to weigh between 11g and 13g. Give your answer correct to the nearest percent.
my answer:
\(\displaystyle \L\\\begin{array}{l}
\frac{{13 - 12}}{{.5}} = 2 \\
\frac{{11 - 12}}{{.5}} = - 2 \\
\end{array}\)
\(\displaystyle \L\\p\left( { - 2 \le Z \le 2} \right) = normcdf( - 2,2) = .954499876 = 95.45\%\)
Let me know what you think
Thank you
Louise
The standard deviation of the following population, correct to two decimal places is:
\(\displaystyle \L\\\left\{ {25,31,33,50,72,81,85,90,93} \right\}\)
my answer: \(\displaystyle \L\\\sigma = 25.93\)
Question #2
The weight of each piece of bubble gum produced by a machine is normally distributed with a mean of 12g and a standard deviation of 0.5g. Determine the percentage of pieces of bubble gum which will be expected to weigh between 11g and 13g. Give your answer correct to the nearest percent.
my answer:
\(\displaystyle \L\\\begin{array}{l}
\frac{{13 - 12}}{{.5}} = 2 \\
\frac{{11 - 12}}{{.5}} = - 2 \\
\end{array}\)
\(\displaystyle \L\\p\left( { - 2 \le Z \le 2} \right) = normcdf( - 2,2) = .954499876 = 95.45\%\)
Let me know what you think
Thank you
Louise