Math203 Ch6 Examples ed7

# Math203 Ch6 Examples ed7 - USING THE Z-TABLE Ex 1 Find the...

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USING THE Z-TABLE Ex. 1) Find the area under the normal distribution curve. Between z=0 and z=0.75 Start by drawing the standard normal curve and shading the desired area. The shaded area does not look like that in the chart. The chart will give from negative infinity (the left) to 0 and from negative infinity(the left) to 0.75. We can subtract the two areas/probabilities to determine the answer. 0.7734 – 0.5 = 0.2734 The area (probability) is 0.2734 Ex 2) Find the area under the standard normal curve between z=0.79 and z=1.28. Start by drawing the standard normal curve and shading the desired area. The table gives negative infinity to 0.79 and negative infinity to 1 Subtracting the values from the tables gives us the shaded piece. .28. in.) 0.8997 – 0.7852 = 0.1145 (If you subtract in the wrong order, the answer will be negative. Just switch the values and subtract aga Area/probability 0.1145 Ex. 3) Find the probability. P( z > 2.83) Start by drawing the standard normal curve and shading the desired area. The chart gives from negative infinity to 2.83. The total area/probability must equal 1. So, we can subtract 1 from the value we obtain in the chart. 1-0.9977 = 0.0023 Or we can use symmetry to determine the answer. Because of symmetry, this is the same as asking for negative infinity to -2.83. That would then look like the left-side of the charts (see the picture at the bottom of the chart). Once we look up -2.83, then we are done. We do not change the 0.0023 that we are obtaining from the chart because probabilities are always positive. The probability (area) is 0.0023. Ex 4) Find the z value that corresponds to the given area. 0.75 0 0 0.79 1.28 0 2.83 0.8962

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The left chart gives the non-shaded area. Our total probability must add up to 1. So, 1-0.8962 = 0.1038 would have been the value we would have obtained from the inside of the chart. Matching it up to it’s corresponding z-value of -1.26. OR.
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Math203 Ch6 Examples ed7 - USING THE Z-TABLE Ex 1 Find the...

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