1. First, put the range in order and then divide the set into quarters. In this case, quartiles are between numbers. <span>83, 85, 89, l 91, 95, 104, l 112, 118, 118, l 125, 134, 138 Q</span>₁ = (89 + 91)/2 = 90 Q₂ = (104 + 112)/2 =108 Q₃ = (118 + 125)/2 = 121.5 Interquartile range (IQR) = Q₃ - Q₁ = 121.5 - 90 IQR = 31.5 2. To find the standard deviation follow the simple steps. Formula in finding the standard deviation: (see attached file) Step 1. Work out the simple average of the numbers (mean) <span><span><u>212 + 249 + 212 + 248 + 239 + 212 + 216 + 234 + 248</u> </span> 9 = <span><u>2070</u> </span> 9 mean (</span>μ) = 230
Step 3. Add all the squared results and get the mean. <span><u>2274</u> </span> 9 Variance = 252.6666667 Step 4. Get the square root of the variance. √252.6666667 = 15.89549202
You find how many numbers are above 10. Then find the frequency and add them together, that will be your numerator. The total number of tries is 200, that is your denominator.
