1)in 2013, babies born during a gestation period of 32 to 35 weeks had a mean weight of 2545 grams and a standard deviation of 660 grams, In the same year ,babies born during a gestation period of 38 to 40 weeks had a mean weight of 3426 grams and a standard deviation of 482 grams.

a)find the z-score for a 34 week gestation period baby that weights 565 grams:

b)find the z-score for a 39 week gestation period baby that weighs 2462 grams:

2)for a standard normal distribution,find: p(z>-1.42)

3)suppose that a brand of lightbulb lasts on average 1686 hours with a standard deviation of 130 hours, assume the life of the lightbulb is normally distributed, calculate the probability that a particular bulb will last from 1271 to 2053 hours? P(1271

Enter your answer as a number accurate to four decimal places.

Note:all z-scores must be rounded to the nearest hundredth.

4)Assume that the readings at freezing on a bundle of thermometers are normally distributed with a mean of 0 degree Celsius and a standard deviation of 1.00 degree Celsius, a single thermometer is randomly selected and tested , find the probability of obtaining a reading between 2.401 degree Celsius and 3.007 degree Celsius. P(2.401

5)Assume that the readings at freezing on a bundle of thermometers are normally distributed with a mean of 0 degree Celsius and a standard deviation of 1.00 degree Celsius, A single thermometer is randomly selected and tested, find the probability of obtaining a reading greater than 2.913 degree Celsius. P(z>2.913)

6)Assume that the readings at freezing on a bundle of thermometers are normally distributed with a mean of 0 degree Celsius and a standard deviation of 1.00 Celsius, A single thermometer is randomly selected and tested, find the probability of obtaining a reading greater than -1.879 degree Celsius. P(z>-1.879)=

7)Assume that the readings at freezing on a bundle of thermometers are normally distributed with a mean of 0 degree Celsius and a standard deviation of 1.00 Celsius, A single thermometer is randomly selected and tested, find the probability of obtaining a reading between 0 degree Celsius and 1.086 degree Celsius. P(0

8)About ......% of the area under the curve of the standard normal distribution is between z= -1.761 and z= 1.761 (or within 1.761 standard deviations of the mean)

9)About.......% of the area under the curve of the standard normal distribution is outside the interval z= [ -0.07 , 0.07 ] (or beyond 0.07 standard deviations of the mean)