chore: update example and add missing space in stats/base/dists/normal/mean

PR-URL: #12104
Reviewed-by: Athan Reines <kgryte@gmail.com>

Author: Planeshifter

lib/node_modules/@stdlib/stats/base/dists/normal/mean/examples/c/example.c

@@ -33,7 +33,7 @@ int main( void ) {
 
 	for ( i = 0; i < 10; i++ ) {
 		mu = random_uniform( -5.0, 5.0 );
-		sigma = random_uniform( 0.0, 20.0 );
+		sigma = random_uniform( 0.1, 20.0 );
 		y = stdlib_base_dists_normal_mean( mu, sigma );
 		printf( "µ: %.4f, σ: %.4f, Mean(X;µ,σ): %.4f\n", mu, sigma, y );
 	}

lib/node_modules/@stdlib/stats/base/dists/normal/mean/test/test.native.js

@@ -97,7 +97,7 @@ tape( 'the function returns the expected value of a normal distribution', opts,
 	sigma = data.sigma;
 	for ( i = 0; i < mu.length; i++ ) {
 		y = mean( mu[i], sigma[i] );
-		if ( expected[i] !== null) {
+		if ( expected[i] !== null ) {
 			if ( y === expected[i] ) {
 				t.strictEqual( y, expected[i], 'mu:'+mu[i]+', sigma: '+sigma[i]+', y: '+y+', expected: '+expected[i] );
 			} else {