We will show in the next chapter that if x1 and x2 are independent with xi ∼ n (µi, σ2 i ), then x1 + x2 ∼ n (µ1 + µ2, σ2 1 + σ 2 2). use this result to find p(x < y ) for x ∼ n (a, b), y ∼ n (c, d) with x and y independent. hint: write p(x < y ) = p(x − y < 0) and then standardize x − y . check that your answer makes sense in the special case where x and y are i. i.d.

An appliance store sells a washer-dryer combination for $1800. if the washer costs $300 more than the dryer, find the cost for each appliance.

On new year's day, the average temperature of a city is 5.7 degrees celsius. but for new year's day 2012, the temperature was 9.8 degrees below the average. i) if a represents the average temperature on new year's day and 7 represents the temperature on new year's day 2012, what formula accurately relates the two values together? ii) what was the temperature on new year's day 2012? dt a 0.8 ii) - 4 1 degrees celsius da-t-98 ii) 59 degrees celsius 1) 7 = -9,8 11) 59 degrees celsius ii) l degrees celsius

0if x and y vary inversely and y=6 as x=7, what is the constant of variation?