What is the standard deviation of the standard normal distribution? «math xmlns=¨http://www.w3.org/1998/Math/MathML¨»«mi»§#963;«/mi»«mo»=«/mo»«/math» {#2}

1. To the left of z = 1.36
   {#1}
   
   
2. To the left of z = 1.96
   {#2}
   
   
3. To the right of z = -0.65
   {#3}
   
   
4. To the right of z = 1.28
   {#4}
   
   
5. To the left of z = -2.575
   {#5}
   
   
6. To the right of z = 1.615
   {#6}
   
   
7. Between z = 0 and z = 1.54
   {#7}
   
   
8. Between z = -1.53 and z = 0
   {#8}
   
   
9. Between z = -1.96 and z = 1.96
   {#9}
   
   
10. To the left of z = -1.28 and to the right of z = 1.28
    {#10}

1. To the left of z = 0.08
   {#1}
   
   
2. To the left of z = 1.28
   {#2}
   
   
3. To the right of z = -1.95
   {#3}
   
   
4. To the right z = 3.25
   {#4}
   
   
5. To the left of z = -3.16
   {#5}
   
   
6. To the right of z = 2.51
   {#6}
   
   
7. Between z = 0 and z = 2.86
   {#7}
   
   
8. Between z = -0.51 and z = 0
   {#8}
   
   
9. Between z = -2.33 and z = 2.33
   {#9}
   
   
10. To the left of z = -1.96 and to the right of z = 1.96
    {#10}

You work for a consumer watchdog publication and are testing the advertising claims of a lightbulb manufacturer.  The manufacturer claims that the life span of the bulb is normally distributed, with a mean of 2000 hours and a standard deviation of250 hours.  You test 20 lightbulbs and get the following life spans.

1. Use your graphing calculator to to construct a frequency histogram of the data with 5 classes.  Is it reasonable to assume that the life span is normally distributed?
   {#1}
   
   
2. Find the mean and standard deviation of your sample to three significant figures.
   «math xmlns=¨http://www.w3.org/1998/Math/MathML¨»«mi»§#956;«/mi»«mo»=«/mo»«/math» {#2}
   «math xmlns=¨http://www.w3.org/1998/Math/MathML¨»«mi»§#963;«/mi»«mo»=«/mo»«/math» {#3}