The publishers of Men are from Mars and Women are from Venus still believe that their book increases relationship happiness. They ran their own experiment (N = 500) in which relationship happiness was measured after participants had read their book and after reading a statistics book (participants read the books in counterbalanced order with a six-month delay.)

Descriptives MEN STATBOOK N 500 500 Missing 0 0 Mean 20.0 18.5 Median 20.0 19.0 Standard deviation 9.98 8.99 Variance 99.6 80.8 Minimum -18.0 -8.00 Maximum 45.0 42.0 Skewness -0.0677 0.0555 Std. error skewness 0.109 0.109 Kurtosis 0.482 -0.116 Std. error kurtosis 0.218 0.218 Shapiro-Wilk W 0.993 0.996 Shapiro-Wilk p 0.017 0.266 MEN 0 density Standardized Residuals 2 -20 20 40 -2 2 MEN Theoretical Quantiles