S TAT 1000: S EMINAR 11 Mitchell Thompson

 Purpose: To test the hypothesis that greater intolerance in women would be associated with lesser responsiveness of specific mechanisms that underlie blood regulation.  Terms:  Orthostatic Compromise – “head rush” caused by sudden drop in blood pressure when a person stands up right  Isoprotenol- a drug that has various effects on the cardiovascular system such as HR

 Variable Situation ??  Two-sample vs. Paired Study  P AIRED S TUDY  Sample vs. Population  M EN (n=10) W OMAN (n=7)

 All subjects were non-smokers and normotensive  Selection of screening based on results of screening evaluation  selection bias?  Female subjects were: tested during the follicular phase of their menstrual cycle, not pregnant, not using oral contraceptives  Individuals with history of hyperthyroidism or taking R x drugs were excluded  Why?  To decrease the amount of confounding variables Table 1. Subject descriptive data VariableMen (n = 10)Women (n = 7)FP Age, yr38 ± 2 36 ± Height, cm175 ± ± Weight, kg78.9 ± ± Estimated body fat, % 14.7 ± ± Rest SBP, mmHg122 ± ± Rest DBP, mmHg74 ± 2 70 ± Rest heart rate, beats/min52 ± 2 65 ± Max heart rate, beats/min 184 ± ± V O 2 max, ml · kg 1 · min ± ± V O 2 max, ml · kg LBM 1 · min ± ± Values are means ± SE. SBP, systolic blood pressure; DBP, diastolic blood pressure; O 2 max, maximal oxygen uptake; LBM, lean body mass.

Copyright ©1998 American Physiological Society Convertino, V. A. Am J Physiol Regul Integr Comp Physiol 275: R1909-R Fig. 6.  Explanatory/Response?  Isoprotenol (explanatory)  HR (response)  + or – Relationship?  positive (+)  linear equation for females is y = 1,880x males is y = 1,303x

Copyright ©1998 American Physiological Society Convertino, V. A. Am J Physiol Regul Integr Comp Physiol 275: R1909-R Fig. 6.  Explanatory/Response?  Isoprotenol (explanatory)  LVR (response)  + or – Relationship?  negative (-)  linear equation for females is y = -865x males is y = -690x

SCATTER PLOT (LESS ERROR) BOX PLOT (LESS SPREAD)

SCATTER PLOT (MORE ERROR) BOX PLOT (MORE SPREAD)

 Strong or Weak?  Iso vs. HR ▪ Females: r= + √0.995 = ▪ Males: r= + √0.993 =  Iso v. LVR ▪ Females: r= -√0.957 = ▪ Males: r = -√0.876 =  Correlation based on average tends to overstate strength because scatter due to individuals has been reduced.

 Question: Does bias arise in the sample or design?  Answer: Tricky  The sample of men and women are taken from the Air Force Base  Sample is not representative of general population

 LBNP tolerance was significantly lower in females than males who matched for age and aerobic fitness in the Air Force.  G-suit designed