Page Load Speed is an important part of conversions rate optimization. There are several formal studies that recognize the loss of sales and conversions correlating directly with load speeds on a website.

• A study at Amazon showed a 1% decrease in sales for every 0.1s decrease in response times. (Kohavi and Longbotham 2007)
• According to studies by the Aberdeen Research Group the average impact of a 1-second delay meant a 7% reduction in conversions.

Psychology of Page Load Speeds

Slow web pages lower perceived credibility (Fogg et al. 2001) and quality (Bouch, Kuchinsky, and Bhatti 2000). Keep your page load times below tolerable attention thresholds, and users will experience less frustration (Ceaparu et al. 2004), lower blood pressure (Scheirer et al. 2002), deeper flow states (Novak, Hoffman, and Yung 2000), higher conversion rates (Akamai 2007), and lower bailout rates (Nielsen 2000).

Test load speed here: https://gtmetrix.com

Here's an example of the output GTMetirx produces regarding website page load speed.