4. The mean life of a battery is 50 hours with a standard deviation of 6 hours with an approximately normal shape. The
manufacturer advertises that they will replace all batteries that last less than 40 hours. If 50,000 batteries were
produced, how many should they expect to replace? Use the population standard deviation.

Which expression is equivalent to (3^2)^-2 a.-81 b.-12 c.1/81 d.1/12

Which themes are portrayed in this excerpt from leo tolstoy’s the death of ivan ilyich? praskovya fedorovna came of a good family, was not bad looking, and had some little property. ivan ilyich might have aspired to a more brilliant match, but even this was good. he had his salary, and she, he hoped, would have an equal income. she was well connected, and was a sweet, pretty, and thoroughly correct young woman. to say that ivan ilyich married because he fell in love with praskovya fedorovna and found that she sympathized with his views of life would be as incorrect as to say that he married because his social circle approved of the match. he was swayed by both these considerations: the marriage gave him personal satisfaction, and at the same time it was considered the right thing by the most highly placed of his associates. so ivan ilyich got married. conforming to social conventions criticism of a middle class lifestyle the destructive impact of loneliness struggling to face reality the necessity of companionship

Determine the mean and variance of the random variable with the following probability mass function. f(x)=( 729divided by 91) (1 divided by 9) superscript x baseline comma x equals 1,2,3 round your answers to three decimal places (e. g. 98.765).