Question

A medical researcher wants to begin a clinical trial that involves systolic blood pressure (SBP) and cadmium (Cd) levels. However, before starting the study, the researcher wants to confirm that higher SPB is associated with lower Cd levels. Below are the SBP and Cd measurements for a sample a participants. What can the researcher conclude with 𝛼 = 0.10?

Cd

55.9

55.7

55.7

55.5

55.9

55.8

55.8

55.5

55.7

55.8

55.6

SBP

169

161

115

113

182

126

179

127

148

160

140

Answer 1

A negative correlation $R$ is a relationship between two variables in which an increase in one variable is associated with a decrease in the other.

Null hypothesis $H_0$ : $R<0$

Alternative hypothesis $H_A$ : $R=0$ or $R>0$

Using online calculator (www.socscistatistics.com) we get:

$R=0.7254$

p-value$=0.5262$

Since p-value is larger than the significance level, we accept the null hypothesis. So, the researcher can conclude that higher SPB is associated with lower Cd levels.