Chapter 23: Problem 9
Two fair dice are thrown. Calculate the probability that the total is (a) 9 (b) 13 (c) more than 9
Chapter 23: Problem 9
Two fair dice are thrown. Calculate the probability that the total is (a) 9 (b) 13 (c) more than 9
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Get started for freeThe probability that a motor will malfunction within 5 years of manufacture is \(0.03\). Out of eight motors calculate the probability that within 5 years of manufacture (a) all eight will malfunction (b) six will malfunction (c) none will malfunction.
The resistances of 50 resistors are measured and the results recorded as follows: $$ \begin{array}{cc} \hline \text { Resistance }(\Omega) & \text { Frequency } \\ \hline 5.0 & 17 \\ 5.5 & 12 \\ 6.0 & 10 \\ 6.5 & 6 \\ 7.0 & 5 \\ \hline \end{array} $$ Calculate the standard deviation of the measurements.
Studies of a particular type of car tyre show that the mileage for which it can be used legally follows a normal distribution with mean 38000 miles and standard deviation 2500 miles. The manufacturers claim that ' 9 out of 10 of our tyres last more than 35000 miles'. Is the claim justified?
Out of 6000 components, 39 fail within 12 months of manufacture. (a) Calculate the probability that a component picked at random fails within 12 months of manufacture. (b) A batch contains 2000 components. How many of these would you expect to fail within 12 months?
The diameters of ball bearings produced in a factory follow a normal distribution with mean \(6 \mathrm{~mm}\) and standard deviation \(0.04 \mathrm{~mm}\). Calculate the probability that a diameter is (a) more than \(6.05 \mathrm{~mm}\), (b) less than \(5.96 \mathrm{~mm}\), (c) between \(5.98\) and \(6.01 \mathrm{~mm}\).
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