Dr. farah is an educational psychologist who is interested in studying the potential causal relationship between doing homework and academic achievement. in january, dr. farah has her students report their fall gpa (a measure of academic achievement) and estimate how many hours they spent doing homework during a typical week in the fall semester. in may, dr. farah measures the same variables again (the estimated number of hours spent doing homework during a typical week in the spring semester and their spring gpa). she finds the following correlations. 5 is an example of which of the following types of correlations?
a. cross-sectional correlation
b. autocorrelation
c. multivariate correlation
d. cross-lag correlation

A41-year-old man comes to the clinic complaining of a chronic cough over the past 4 months, which has now been accompanied by haemoptysis. he denies smoking or any past medical history. on physical examination, his head and neck examination is normal. his lungs have diffuse bilateral rales. cardiac examination is normal. laboratory findings reveal na 142 meq/l, k 4.2 meq/l, cl 110 meq/l, hco3 24 meq/l, bun (blood urea nitrogen) 39 mg/dl, creatinine 2.9 mg/dl. urinalysis reveals microscopic haematuria and 4+ proteinuria. which of the following serologic blood tests would most confirm the suspected diagnosis? - anti-glomerular basement membrane antibodies- anti-mitochondrial antibodies- anti-neutrophilic antibodies- anti-parietal cell antibodies- anti-smooth muscle antibodies