Square root of the Variance:

Presentation on theme: "Square root of the Variance:"— Presentation transcript:

Square root of the Variance:
AP Stats Chapter 6 Review Standard Deviation Square root of the Variance: But use a calculator!! STAT CALC 1-VAR Stats -or- 2nd STAT MATH stdDev(

Determines number of standard deviations from the mean:
AP Stats Chapter 6 Review Z - Scores Determines number of standard deviations from the mean:

GOALS: move center (mean) to zero change units to standard deviations
AP Stats Chapter 6 Review Standardizing GOALS: move center (mean) to zero change units to standard deviations

Standardizing Shift Left/Right – ADD constant to everything EXCEPT
AP Stats Chapter 6 Review Standardizing Shift Left/Right – ADD constant to everything EXCEPT spread: range, IQR, standard deviation

Changing Spread (units) – MULTIPLY EVERYTHING by constant!
AP Stats Chapter 6 Review Standardizing Changing Spread (units) – MULTIPLY EVERYTHING by constant!

Normal Model +/- 1 std.dev.
AP Stats Chapter 6 Review Normal Model +/- 1 std.dev.

Normal Model +/- 2 std. dev.
AP Stats Chapter 6 Review Normal Model +/- 2 std. dev.

Normal Model +/- 3 std.dev.
AP Stats Chapter 6 Review Normal Model +/- 3 std.dev.

Graphing a Normal Model TI-83
AP Stats Chapter 6 Review Graphing a Normal Model TI-83 Enter a formula in ‘y=‘ Defaults: mean=0, std.dev.=1 Turn all STAT PLOTS OFF You will need to set the window to fix xmin, xmax, xscale. ZOOM – 0 (zoomFit)

Z-Scores Percentiles TI-83
AP Stats Chapter 6 Review Z-Scores Percentiles TI-83 To find the percentage of data that fall below a given z-score*: If min is , use –9999 If max is , use 9999 Defaults: mean=0, std.dev.=1 *you can also use the z-table

Z-Scores Percentiles TI-83
AP Stats Chapter 6 Review Z-Scores Percentiles TI-83 To find the z-score that cuts off a percentage of data*: Defaults: mean=0, std.dev.=1 *you can also use the z-table

Z-Scores Percentiles TI-83
AP Stats Chapter 6 Review Z-Scores Percentiles TI-83 To SHADE the desired area given z-scores: Be sure model has been graphed using ‘y=‘ Clear any previous shading by  2nd DRAW ClrDraw Enter z-scores: 2nd DISTR DRAW If min is , use –9999 If max is , use 9999 Defaults: mean=0, std.dev.=1

Are You Normal? Is a normal model the best for your data?
AP Stats Chapter 6 Review Are You Normal? Is a normal model the best for your data? To find out, do a Normal Probability Plot Enter data into L1 Turn a STAT PLOT ON Select the last ‘Type’ (looks like a line graph) Select the correct Data List Choose ‘Y’ for Data Axis Specify the Mark you want (it doesn’t matter) ZoomStat The more ‘linear’, the more ‘normal’!